Volume 63, Issue 1

The cement and construction industry creates around 10% of the global carbon footprint. Geopolymer and alkali-activated concrete provide a sustainable solution to conventional concrete. Due to its disadvantages, the practical usage of geopolymer and alkali-activated concrete is limited. Workability is one of the issues faced in developing geopolymer and alkali-activated concretes. Plenty of research was conducted to provide a solution to enhance the ability to use different superplasticizers (SPs). The present article extensively reviews the effects of SPs on geopolymer and alkali-activated concretes. The research articles published in the last 5 years in high-quality journals are considered for the chemical composition of the different SPs and analyses of their exact impact on geopolymer and alkali-activated cement mortar and concrete. Later, the impact of SPs on the normal consistency and setting times of cement mortar, workability, compressive strength, flexural strength, split tensile strength, microstructure, and water absorption of geopolymer and alkali-activated concrete was determined. SPs improve the geopolymer and alkali-activated concretes upon their use in desired dosages; more dosage leads to negative effects. Therefore, selecting the optimal superplasticizer is essential since it impacts the performance of the geopolymer and alkali-activated concrete.

The construction sector has been under growing public attention recently as one of the leading causes of climate change and its detrimental effects on local communities. In this regard, geopolymer concrete (GPC) has been proposed as a replacement for conventional concrete. Predicting the concrete’s strength before pouring is, therefore, quite useful. The mechanical strength of slag and corncob ash (SCA–GPC), a GPC made from slag and corncob ash, was predicted utilizing multi-expression programming (MEP). Modeling parameters’ relative importance was determined using sensitivity analysis. When estimating the compressive, flexural, and split tensile strengths of SCA–GPC with MEP, 0.95, 0.93, and 0.92 R 2 -values were noted between the target and predicted results. The developed models were validated using statistical tests for error and efficiency. The sensitivity analysis revealed that within the mix proportions, the slag quantity (65%), curing age (25%), and fine aggregate (3.30%) quantity significantly influenced the mechanical strength of SCA–GPC. The MEP models result in distinct empirical equations for the strength characteristics of SCA–GPC, unlike Python-based models, which might aid industry and researchers worldwide in determining optimal mix design proportions, thus eliminating unneeded test repetitions in the laboratory.

Research attention in powder metallurgy (PM) processing of high-entropy alloys (HEAs) is rising. Some reviews have been published but a detailed historical analysis to identify the thematic research areas and prospective future research areas is lacking. Therefore, this study presents a bibliometric literature analysis of PM-processed HEAs by mapping and clustering 700 articles published between 2007 and August 2022 in the Scopus database. The most prolific authors, their collaborators, institutions, and most preferred journals publishing PM-HEA works are identified and mapped. Publication trend shows that significant research attention in the PM processing of HEAs began to gain traction in 2016. The top three journals in this field are Journal of Alloys and Compounds, Materials Science and Engineering A, and Intermetallics . However, co-authorship network analysis does not reveal significant inter-institutional research collaboration indicating that strengthening this area could help to accelerate scientific discovery, enhance technology transfer, and commercialization of HEA products. Based on the co-occurrence frequencies of author keywords, popular research directions are identified, and a systematic review of emerging functional applications is undertaken. This work provides a comprehensive visual reference guide for researchers to deepen their knowledge of this field and delivers insight into prospective future research opportunities to stimulate further ground-breaking works.

This study thoroughly reviews the recent design methods for ultra-high-performance concrete (UHPC) with agricultural waste. The goal is to identify UHPC composites that meets environmental sustainability requirements while fulfilling workability, durability, and mechanical properties. The capacity of typical review studies is limited in bridging the various literature aspects systematically. The article includes comparative analyses identifying these methods’ intrinsic connections and current trends. The analysis indicates that 71% of documents on incorporating agricultural waste into UHPC are in the “Engineering” and “Materials Science” disciplines, with 69% being journal articles, and 27% conference documents. Significant research keywords involve “Ultra-High-Performance Concrete,” “Cements,” “Sustainable Development,” and “Agricultural Wastes,” highlighting the extensive exploration of agricultural waste in UHPC. It has been discovered that agricultural waste can replace silica fume in UHPC, improving strength and durability by reducing pore volume and enhancing microstructure. Substituting 5–30% of cement with rice husk ash significantly boosts compressive strength, enhancing cement hydration, pore structure, and pozzolanic reaction, offering substantial environmental benefits and supporting the construction industry’s contribution to low-carbon sustainable development. This article provides guidance and recommendations for developing sustainable UHPC to meet diverse design specifications, promoting environmentally friendly construction practices.

One of the most popular and widely used cementitious nanoparticle materials is nanosilica (NNS). Although several researchers discuss how NNS affects the characteristics of concrete, knowledge is dispersed, making it difficult for the reader to assess the precise advantages of NNS. Therefore, a detailed review is required for the substitution of NNS in concrete. The present reviews collect the recently updated information on NNS as concrete ingredients. First, a summary of the manufacturing, physical, and chemical characteristics of NNS is provided. Second, the characteristics of fresh concrete are examined, including its effect on setting time, flowability, air content, and fresh density. Third, strength properties such as compressive, tensile, and flexure capacity are discussed. Finally, microstructure analyses such as scanning electronic microscopy and X-ray diffraction are discussed. The results show that NNS enhanced the mechanical and durability of concrete due to the pozzolanic reaction and microfilling voids but decreased the slump flow. The optimum dose is important for maximum performance. The typical optimum dose of NNS varies from 1 to 3% by weight of cement. This article also suggests future research directions to improve the performance of NNS-based concrete.

Foam concrete or foamcrete is a lightweight, porous material with a wide range of applications in the construction domain. This article focused on reviewing porosity, thermal conductivity, acoustic properties, compressive strength ( f c ′), elastic modulus ( E ), flexural strength ( f y ), stability, resistance to hostile environments, density, and fire resistance of foam concrete. A systematic literature analysis was conducted to identify relevant research trends on foam concrete. The challenges and limitations of foam concrete research were highlighted, including the lack of standardized testing methods and the need for more research on the long-term durability and structural performance of foam concrete. The analysis of the literature data revealed that there had been a growing interest in foamcrete research over the past decade. Foam concrete may be utilized in several construction applications due to its adaptability and wide range of uses. Its potential uses can be increased by developing new manufacturing methods and the inclusion of certain admixtures. The present research has the potential to be advantageous for scholars interested in collaborative advancement and the exchange of novel tactics and concepts, owing to the visual and statistical representation of the regions/countries and researchers that have contributed.

Poly-ether-ether-ketone (PEEK), a biomaterial renowned for its mechanical prowess and biocompatibility, is increasingly preferred for medical implants. Its natural bone-like mechanical property, ease of manipulation, and ability to mitigate stress shielding render it a standout replacement for titanium in dental implantology. Adding carbon fiber and graphene to PEEK can further enhance the mechanical properties of PEEK. However, the biological passivity of PEEK hampers its efficacy in bone repair, driving spurring research into surface modifications to enhance its bioactivity. Incorporating metal, inorganic, and organic antimicrobial agents is anticipated to bolster PEEK’s resistance to bacteria, thereby reducing the risk of acute postoperative infections and peri-implantitis. Apart from its antimicrobial activity, researchers have also investigated methods to enhance the osteogenic properties of PEEK. These approaches include surface modification and blending modification. Surface modification includes physical modification, chemical modification, and biologically active substance modification. These methods can further enhance the implant integration and durability, potentially improving patient outcomes. This overview examines PEEK’s processing techniques and highlights recent research achievements in improving its biomechanical, antibacterial, and osteogenic properties. Considering these strides, we argue that modified PEEK holds significant promise as a material for dental implants, charting an encouraging course for its clinical future.

It is a well-known fact that many sophisticated works consume a lot of human resources, leading to the need to find effective alternative. The manufacturing industry demands a lot of human resources, with around half of the global working population participating in this sector. Challenges such as sudden conflicts in the data, disasters, and loss of productivity are encountered by the manufacturing industries and can be overcome by monitoring machine performance data and automatically configuring the machines according to changing needs. This emphasizes the importance of the Internet of Things (IoT) in addressing niche areas of manufacturing. IoT is a buzzword heard everywhere around the globe. Implementing this technology makes most of the work more accessible than other conventional methods. This has created a lot of research interest on this topic. Among many manufacturing sectors, polymer composite material manufacturing is one of the most demanding. This review article purely focuses on polymer composite manufacturing and its allied processes. The consolidation of data is based on the influence of IoT on the extraction of fibers and manufacturing of polymer composite material using novel techniques, quality assessment of manufactured polymer composite material, challenges faced in exploring the use of IoT, and future scope. It can be stated from the survey that various researchers have minimally explored the incorporation of IoT, but its future looks very promising in terms of producing high-quality products at less time and lower cost by integrating this technique with conventional methods.

With the continuous development of hypersonic vehicles, higher demands are being placed on all aspects of the performance of thermal protection materials. Carbon fiber reinforced ultra-high temperature ceramics composites (C f /UHTCMC) have an extremely bright prospect as thermal structures and anti-ablation components of hypersonic vehicles and rockets, by reason of their superior thermal shock, oxidation and ablation properties, high fracture toughness, and damage tolerance. However, due to the complicated fabrication process and harsh service environment of C f /UHTCMC, there are still some pivotal scientific issues that need to be clarified on structural evolution and performance mechanisms. The aim of this work is to review the latest research progress in processing methods, matrix modification, oxidation ablation mechanism, structure, and property regulation as well as elevated temperature mechanical properties of C f /UHTCMC, summary, and prospect of the future research trend of C f /UHTCMC, to provide reference for further promoting the improvement and development of C f /UHTCMC.

The development of auxetic materials, known for their unique negative Poisson’s ratio, is transforming various industries by introducing new mechanical properties and functionalities. These materials offer groundbreaking applications and improved performance in engineering and other areas. Initially found in natural materials, auxetic behaviors have been developed in synthetic materials. Auxetic materials boast improved mechanical properties, including synclastic behavior, variable permeability, indentation resistance, enhanced fracture toughness, superior energy absorption, and fatigue properties. This article provides a thorough review of auxetic materials, including classification and applications. It emphasizes the importance of cellular structure topology in enhancing mechanical performance and explores various auxetic configurations, including re-entrant honeycombs, chiral models, and rotating polygonal units in both two-dimensional and three-dimensional forms. The unique deformation mechanisms of these materials enable innovative applications in energy absorption, medicine, protective gear, textiles, sensors, actuating devices, and more. It also addresses challenges in research, such as practical implementation and durability assessment of auxetic structures, while showcasing their considerable promise for significant advancements in different engineering disciplines.

The necessity for a shift to alternative forms of energy is highlighted by both approaching consequences of climate change and limited availability of fossil fuels. While a large portion of energy required can be generated by solar and wind, a diverse, sustainable energy generation mix is still necessary to meet our energy needs. By capturing otherwise lost heat energy and turning it into valuable electrical energy, thermoelectric can play a significant part in this. Using the Seebeck effect, thermoelectric generators (TEG) have established their capability to transform thermal energy into electrical energy directly. Furthermore, because they do not include chemical compounds, they are silent in operation and can be built on various substrates, including silicon, polymers, and ceramics. Moreover, thermoelectric generators have a long operational lifetime, are position independent, and may be integrated into bulky, flexible devices. However, the low conversion efficiency of TEG has confined their broad application, hampering them to an academic subject. Until now, recent developments in thermoelectric generators and devices are presuming the technology to catch its place among state-of-the-art energy conversion systems. This review presents the commonly used methods for producing thermoelectric modules (TEMs) and the materials currently studied for TEMs in bulk and printed thermoelectric devices.

This review article investigates the properties and applications of polyetheretherketone (PEEK) in the field of dental implantology. PEEK has emerged as a significant material of interest due to its mechanical strength, biocompatibility, and radiolucency. The article provides a detailed examination of PEEK’s biocompatibility and the various reinforcements that enhance its performance, including PEEK/HA, PEEK/β-TCP–TiO 2 , and CFR-PEEK. Focusing on dental applications, we discuss PEEK’s use in implant abutments, fixed dental prostheses, implants, and its commercial forms available for dental use. Further, the mechanical behavior of PEEK and its composites is analyzed, including its elastic behavior under various stress conditions and wear resistance. Moreover, the article conducts an integrative systematic review on the stress distribution in dental implants or abutments made from reinforced PEEK composites, assessed through finite element analysis. The aim of this review is to provide insights into the current state of research, the benefits, challenges, and future prospects of PEEK in implantology, and the biomechanical evaluation methods that underpin the development of this promising material.

Demographic change is causing society to age. At the same time, technological progress is changing the way ageing individuals are cared for and medically treated. Several smart wearables and garments have recently been developed for this purpose. Based on previous research, we see a research gap in the use of smart clothing in the care and support of elderly people, especially with regard to concrete application potentials and example products. The aim of this study was to provide an overview of the latest studies and developments in smart clothing with a focus on usability and acceptance for an elderly individuals. A systematic literature search was performed in five databases using a predefined set of keyword. A total of 169 articles published between 1/2000 and 2/2023 were identified and assessed. The literature search followed a previously prepared research protocol according to the criteria of a systematic literature search. The research field of smart clothing is expanding with smart shirts being a major focus; however other products are also being investigated, each with specific capabilities. In particular, vital parameters are constantly optimized; representative products are described and assessed according to their potential applicability to elderly people. The future applications of smart clothing in health care are promising. Many studies on basic applications of smart textiles have been done, and some studies have already involved older people. Furthermore, newly developed suggestions for possible categorizations of smart wearables as well as smart clothing as a subtype are presented based on the researched literature. We found an overall positive impression of the development and application of smart clothing, especially in geriatric settings. However, aspects such as data collection, skin compatibility, wearing comfort, and integration of geriatric factors into known acceptance models need further investigation. Over the last two decades, there have been many developments in the field of smart clothing. For the care and support of elderly people, smart clothing is an important development with great potential. Continued advancement in these products is needed to adequately address the special needs of older people.

In recent decades, with the advancement of micro-electro-mechanical systems technology, traditional materials have become insufficient to meet the demands of cutting-edge technology for various material properties. Composites have attracted widespread attention as an effective and viable solution. Silicon carbide whiskers (SiCw) have emerged as excellent reinforcements due to their high thermal conductivity, low thermal expansion coefficient, high melting point, superior mechanical properties, and high chemical stability. This article provides a comprehensive review of the reinforcement mechanisms and current research state of SiCw-reinforced composites. The reinforcement mechanisms include mainly grain refinement, load transfer, and crack bridging. The composites are categorized based on the type of the matrix: ceramic-based, metal-based, and polymer-based composites. The influence and parameter performance of the reinforcement mechanism on SiCw-reinforced composite materials with different matrices vary. However, the key to improving SiCw-reinforced composites lies in understanding the interplay of properties between the matrix and the reinforcement, as well as the ordered and regular distribution and binding at the interface. Finally, the current state and limitations of SiCw-reinforced composites are summarized, and future development trends are discussed. This article represents a great contribution to the future applications of SiCw-reinforced composite materials.

Sustainability and the need for biodegradable composites are the two new buzzwords finding prominence in recent times. In this regard, there has been a significant increase in interest regarding natural fiber composites (NFCs) due to their potential to address environmental issues and contribution toward the development of sustainable materials. The aim of this extensive review is to thoroughly investigate the current research landscape, advancements, and applications of NFCs. The study covers a range of topics, including the various types of natural fibers commonly used, their processing techniques, reinforcement strategies, mechanical properties, morphological characteristics, biodegradability, and sustainability. It also explores their potential uses across different industries. Furthermore, this article examines the challenges and opportunities associated with NFCs, as well as their environmental impacts and economic viability. By conducting a detailed analysis of existing literature, this review aims to shed light on the advancements achieved so far and the future potential of NFCs as eco-friendly alternatives to conventional materials. Ultimately, it offers insights into how these materials can enhance sustainability in material engineering.

The emergence of geopolymer concrete (GPC) has occurred as a sustainable substitute for conventional cement-based concrete, offering enhanced mechanical characteristics and reduced environmental impact. In the quest to further optimize GPC, incorporating supplementary cementitious materials has gained attention. For the research, Alccofine-1203 was considered as the material for incorporation into the geo-polymer concrete. This review study specifically examines the utilization of Alccofine-1203 as a material in GPC within the domain of structural engineering. Alccofine-1203, a high-performance mineral additive, exhibits pozzolanic and reactive properties, making it a promising candidate for enhancing GPC performance. This paper provides a comprehensive analysis of the chemical compositions and physical properties of Alccofine 1203, highlighting its potential benefits in GPC. Furthermore, it explores the influence of Alccofine-1203 on various aspects of GPC, including workability, compressive strength, flexural strength, durability, microstructure, and thermal properties. The review encompasses an analysis of relevant tests conducted to evaluate these properties. In summary, this review article is a great resource for researchers, engineers, and practitioners who are interested in the development and application of GPC containing Alccofine-1203.

This review examines recent advancements in surface treatment technologies for aluminum alloys used in sports equipment. We discuss conventional methods like chemical conversion coatings and anodizing, as well as emerging techniques such as plasma electrolytic oxidation, physical vapor deposition, and laser surface modification. The replacement of toxic hexavalent chromium with eco-friendly alternatives is highlighted as a key development. We also explore the potential of smart, self-healing coatings to extend equipment lifespan. Our analysis reveals that while significant progress has been made in enhancing corrosion resistance and mechanical properties, challenges remain in scaling up advanced treatments for industrial implementation. The review concludes that continued innovation in surface treatments will be crucial for improving the performance, safety, and sustainability of aluminum alloys in sports applications, ultimately benefiting athletes and manufacturers alike.

In the field of advanced materials, carbon-based fillers are crucial for crafting high-performance polymer composites. Continual innovations in modifying these fillers are expanding the capabilities of polymer composite materials, heralding new advancements in diverse technological areas. Ionic liquids provide innovative methods for modifying carbon-based fillers to improve the performance of polymer composites. In this concise review, numerous carbon-based fillers used for modification, ionic liquids utilized in the modification, and polymer matrices employed in polymer composites are classified. In addition, the impact of ionic liquids on the interactional and structural properties of carbon-based fillers and their polymer composites, as analyzed via Raman spectroscopy, is concisely explained. This review provides a succinct analysis that deepens the understanding of the Raman spectroscopic results pertaining to various carbon-based fillers and polymer composites. In brief, Raman analyses indicate that carbon-based fillers modified with ionic liquids and their composites exhibit upshifted peak positions and higher intensity ratios compared to their unmodified fillers. The upshifts in peak positions are linked to interactions between the fillers and ionic liquids or between the modified fillers and polymer matrices. Higher intensity ratios in these modified fillers and polymer composites suggest increased structural defects in the fillers.

The aim of this study is to assess the effectiveness of hexagonal boron nitride (hBN) coatings to enhance the corrosion resistance of metals as well as evaluate their crucial toxicological impacts on both the environment and human health. Organic coatings are extensively applied in the field of protecting metals against corrosion. They are preferred as corrosion inhibitors due to their carbonyl and hydroxyl group content, but they have drawbacks regarding brittleness, porosity, and oxidation susceptibility. In this review, we mainly focused on the synthesis, properties, and applications of hBN coatings and emphasized the way to improve corrosion resistance in metals and alloys. Furthermore, our discussion demonstrated that the boron nitride nanosheet (BNNS) coatings significantly improve corrosion resistance, hydrophobicity, and crack mitigation properties. The researchers achieved reduced coating porosity and enhanced protection against corrosive media by effectively dispersing BNNS in organic resin. This study also determines the protective mechanism of BNNS composite coatings against corrosion. Moreover, we addressed the impact of BBNS synthesis and its physicochemical properties on the environment and organisms. Finally, suggestions are made for future research and the sustainability of industrial use to broaden the scope of applications for BNNS composite coating.

The shortcomings of the microarc oxidation (MAO) technology are revealed, in accordance with which a range of topical scientific problems that need to be solved is formulated. It is shown that, despite significant progress in this area of research, there are still controversial issues related mainly to the features of the emergence and combustion of microdischarges. In order to develop a scientifically substantiated approach to the choice of the optimal mode for deposition of microarc oxide coatings, regularities in the influence of heterogeneous factors on their properties are systematized. The analysis of scientific works devoted to the mathematical description of the MAO process has been carried out. It is shown that the existing mathematical models have limitations, and are applicable only to certain aspects of coating formation and do not describe the MAO process as a whole. The prerequisites, recommendations, and theoretical provisions that can be used in the development of a complex mathematical model of the MAO process are revealed. Known methods of analytical description of the forming curve are considered. The possibility of using the forming curve for determining the correct choice of technological parameters and predicting the oxide coating properties during their formation is shown.

This comprehensive review and scientometric analysis address the critical need for sustainable construction practices by examining the utilization of granite waste in concrete. The study responds to mounting environmental challenges in construction waste management, particularly addressing granite processing waste which comprises 50–60% of production [Indian Bureau of Mines. ariMinerals yearbook 2021 (Part-III: Mineral reviews), 60th edn, Granite (Advance Release), Indian Bureau of Mines, Ministry of Mines, Government of India, Nagpur, 2021.]. Through rigorous analysis of 585 publications from 2008 to 2024, the study reveals optimal granite waste replacement levels of 20–25% for sand and 10–15% for cement, yielding enhanced mechanical properties with compressive strengths up to 66 and 72 MPa, respectively. The research emphasizes the crucial role of moisture correction based on saturated surface dry conditions for consistent performance. Key findings demonstrate that granite waste can effectively replace up to 25% of sand and 15% of cement, contributing to reduced landfill use and lower CO 2 emissions. The study identifies research gaps, including limited long-term durability studies and the need for standardization. Future directions propose investigating synergies with other supplementary cementitious materials and applications in emerging concrete technologies. This work provides a framework for optimizing granite waste in concrete, balancing environmental benefits with improved mechanical properties, and offering valuable insights for developing sustainable concrete solutions that potentially reduce environmental impact while enhancing performance.

The dimple of ball grid array (BGA) area with 70 mm × 70 mm size on load board for high performance integrated circuit final test is investigated by shadow moire at first, the dimple of BGA area decreases from 184.3 to 97.1 μm when six additional prepregs with 60 mm × 60 mm size are added at BGA area before hot lamination process. The micromorphology and stress/strain simulation are conducted to improve the coverage and reliability of copper metallization layer in through hole at that BGA area. The microcracks of electroless copper layer at the position of glass fiber and inner layer copper pad, which leads to serious crack after solder float, are well covered by subsequent electroplating copper layer. When the through holes at BGA area with 0.2 mm diameter and 7.0 mm depth are fabricated based on insulating dielectric material used for high-speed signal transmission, the simulation results point out that IT968 is better than M6G for the thermal shock reliability of through hole metallization layer. A load board vehicle with 126 layers and 8.3 mm thickness based on IT968 shows good interconnection structure reliability after 12 times 288°C solder float.

In the rockfall prevention and control project, the reinforced concrete (RC) slab and sand (gravel soil) soil cushion layer are commonly used to form the protection structure, thereby resisting the rockfall impact. Considering that the oversized deformation of the cushion layer under impact load using the finite element simulation cannot converge, this article establishes a numerical calculation model using smoothed particle hydrodynamics–finite-element method coupling (SPH–FEM). First, the standard Lagrange finite-element mesh is established for the whole model using ABAQUS, and then the finite-element mesh of the soil cushion layer is converted to SPH particle at the initial moment of the calculation, and finally the calculation results are solved and outputted. The results indicate that, compared with the results of the outdoor rockfall impact test, the relative errors of the rockfall impact force and the displacement of the RC slab are within 10%, which proves the rationality of the coupling algorithm; moreover, in terms of the numerical simulation, the SPH–FEM coupling algorithm is more practical than the finite element for reproducing the mobility of the rockfall impacting the sand and soil particles. In addition, at an impact speed of less than 12 m·s −1 , the cushion layer is able to absorb more than 85% of the impact energy, which effectively ensures that the RC slab is in an elastic working state under small impact energy and does not undergo destructive damage under large impact energy; the peak impact force of the rockfall is approximately linear with the velocity, and the simulated value of the peak impact force is basically the same as that of the theoretical value of Hertz theory; the numerical simulation is good for reproducing the damage process of the RC slab in accordance with the actual situation. The SPH–FEM coupling algorithm is more justified than the FEM in simulating the large deformation problem, and it can provide a new calculation method for the design and calculation of the rockfall protection structure.

Recycled concrete technology can promote the sustainable development of the construction industry, but the insufficient mechanical properties of recycled concrete have become a key constraint on its development. By adding waste fibers, the mechanical properties of recycled concrete can be improved, and the problem of disposing of waste polypropylene fibers can be solved. In this article, the effects of recycled brick aggregate content and waste fiber content on the mechanical properties and microstructures of recycled brick aggregate concrete through macroscopic mechanical experiments and microstructure experiments are investigated. The results show that the addition of recycled brick aggregate reduces the mechanical properties of concrete; when the content of recycled brick aggregate is 100%, the compressive strength and splitting tensile strength decrease by 22.04 and 20.00%, respectively. The addition of waste fibers can improve the mechanical properties of recycled brick aggregate concrete, but it is necessary to control the contents of waste fibers in a certain range. When the content of waste fibers is 0.08%, the best improvement effect on the mechanical properties of concrete is achieved; the compressive strength of concrete with a 50% (100%) recycled aggregate replacement rate increases by 6.06% (8.90%), while the splitting tensile strength of concrete with a 50% (100%) recycled aggregate replacement rate increases by 2.30% (6.16%). Through microstructural analysis, the mechanism by which waste fiber improves the mechanical properties of recycled brick aggregate concrete is revealed. The addition of waste fibers has the effect of strengthening the framework inside the recycled brick aggregate concrete, forming a good structural stress system and allowing the recycled brick aggregate concrete to continue to bear loads after cracking. In this study, waste brick aggregate and waste fiber are effectively utilized, which can not only reduce pollution to the environment but also realize the sustainable utilization of resources. Graphcal abstract

To clarify the effect and mechanism of hindered amine light stabilizer (HALS) on the UV aging behavior of asphalt binder, T622-HALS was selected as the modifier for UV aging resistance of asphalt. The physicochemical properties and microstructure of T622 light stabilizer were comprehensively analyzed. The light stabilizer-modified asphalt was prepared and placed in the UV radiation chamber for UV aging treatment. Scanning electron microscope and atomic force microscope were used to analyze the microscopic morphology evolution of light stabilizer-modified asphalt induced by UV radiation. The thermal properties and functional group composition changes in light stabilizer-modified asphalt during UV aging were studied by using the thermogravimetric and infrared spectroscopy combined testing system. The decay laws of the physical and rheological performances of light stabilizer-modified asphalt were studied during UV aging process, and the effect of light stabilizer on the UV aging behavior of asphalt binder was clarified. The research results indicated that HALSs could alleviate the microcracks and roughness change on the surface of asphalt and reduce the content of functional groups such as carbonyl and sulfoxide in asphalt. Furthermore, HALS could reduce the value difference of physical and rheological properties of asphalt before and after UV aging, significantly improving the UV aging resistance of asphalt binder.

Composites are becoming materials of the future. Composite applications have become popular in the air as airframes in the aerospace industry to the deepest seas in the form of underwater pipes. A sandwich structure is a composite with cores with low-density material pinned by a stiff facing. In this article, the sandwich material used is a Nomex-Aramid honeycomb as the core and carbon fiber composite as the facing sandwich structure. The main goal of this study is to obtain the characteristics of the sandwich structure, Nomex-Aramid carbon fiber, and study the effect of core variation on the overall strength of the sandwich structure. Numerical simulation testing was carried out to determine the characteristics of the sandwich structure. The loadings carried out were mainly three-point bending, tensile, compression, and torsional tests. In addition, this study also compared the geometry of cores and several materials to study the effect of core properties on the overall strength of the materials. The authors used the finite element method with ABAQUS. A mesh convergence study was also conducted in this article. The results of the numerical simulation showed that the structure sandwich had a major drawback in the local strength caused by the size of the cells used. In addition, the geometric shape and type of the core material also affected the strength of the sandwich structure.

This study aims to investigate the diffusion stabilization process of nano-Co 2 O 3 during the non-precursor transformation of 3Y-TZP. 3Y-TZP was set as the control group, and the experimental groups were 0.1–0.3 mol% nano-Co 2 O 3 -doped 3Y-TZP. The samples were prepared by the ball milling process, isostatic cool pressing, and sintering. All samples were hydrothermally treated at 134°C and 2 bar for different time periods. The resistance to low-temperature degradation of nano-Co 2 O 3 -doped 3Y-TZP was analyzed by X-ray diffraction. The microstructure of zirconia ceramic samples was determined by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and electron paramagnetic resonance studies. The addition of nano-Co 2 O 3 into 3Y-TZP resulted in higher hydrothermal aging resistance than 3Y-TZP. The addition of 0.2 mol% nano-Co 2 O 3 dopants resulted in the highest hydrothermal aging resistance among nano-Co 2 O 3 -doped 3Y-TZP ceramics. The grain sizes of 3Y-0.2Co are smaller than those in the control group. With the increase of cobaltous oxide doping contents, the segregation of Co 3+ ions at the crystal boundary increased. The content of oxygen vacancies on the surface of the sample increased with the increase of the Co 2 O 3 doping content. The oxygen vacancy concentrations of 3Y-0.2Co increased obviously after aging. 3Y-0.1Co, 3Y-0.3Co, and the control showed decreased oxygen vacancy concentrations after aging. Trivalent element doping of 3Y-TZP effectively improved the aging resistance of 3Y-TZP. The addition of 0.2 mol% nano-Co 2 O 3 resulted in the highest hydrothermal aging resistance. Improved aging resistance is attributed to the nano-Co 2 O 3 doping resulting in the 3Y-TZP grain size inhibition, grain boundary segregation of cobalt ions, and oxygen vacancy maintenance. This work is expected to provide an effective reference for the development and application of budget dental materials by regulating grain boundary engineering.

Three reinforcement ratios (0, 50, and 100%) of carbon fiber reinforced plastics (CFRP) were selected to improve the mechanical properties of recycled brick concrete in this study. Utilizing axial compression test, X-ray diffractometer analysis, the evolution of parameters such as compressive strength, peak stress, and elastic modulus of reclaimed concrete were analyzed. The reclaimed brick concrete’ stress distribution and damage mechanism were revealed. The aggregate internal failure and CFRP reinforcement effect mechanism are discussed. The finite element model of red brick concrete reinforced by CFRP under uniaxial compression is established. The constitutive model for CFRP-reinforced recycled brick concrete is proposed.

The corrosion problem of steel-reinforced concrete (SRC) columns in coastal areas is becoming increasingly severe and needs to be solved urgently. This study established a numerical analysis model for SRC middle-length columns considering corrosion effects. The bond–slip constitutive relationship between corroded steel and concrete was established. It was found that when the rust rate is low, the bonding stress of SRC columns is slightly increased compared to those without corrosion. The ultimate and residual bonding stress will decrease significantly when the rust rate exceeds 1.5%. The comparison between the numerical analysis model and the experimental results shows that the establishment of the model is reasonable. Subsequent parameter analysis showed that for corroded SRC mid-length columns, the larger the slenderness ratio of the component, the faster the decrease in axial compression performance. The rust rate increased from 0 to 30%, and the axial compression performance of SRC columns decreased significantly. When the rust rate exceeded 30%, the axial compression performance of concrete columns tended to stabilize. A formula for calculating SRC middle-length columns’ ultimate bearing capacity considering corrosion effects has been proposed.

The introduction of ultrasonic vibration in the grinding process of γ-TiAl intermetallic compounds can significantly reduce its processing difficulty. It is of great significance to understand the grinding mechanism of γ-TiAl intermetallic compounds and improve the processing efficiency by studying the mechanism of ordinary grinding of abrasive grains. Based on this, this study proposes a grinding force prediction model based on single-grain ultrasonic assisted grinding (UAG) chip formation mechanism. First, the prediction model of grinding force is established based on the chip formation mechanism of abrasive sliding ordinary grinding and the theory of ultrasonic assisted machining, considering the plastic deformation and shear effect in the process of material processing. Second, the UAG experiment of γ-TiAl intermetallic compounds was carried out by using diamond grinding wheel, and the unknown coefficient in the model was determined. Finally, the predicted values and experimental values of grinding force under different parameters were compared to verify the rationality of the model. It was found that the maximum deviation between the predicted value of tangential force and the actual value is 23%, and the maximum deviation between the predicted value of normal force and the actual value is 21.7%. In addition, by changing the relevant parameters, the model can predict the grinding force of different metal materials under different processing parameters, which is helpful for optimizing the UAG parameters and improving the processing efficiency.

The study aims to enhance the hardness and wear of copper and Cu–TiO 2 -based composites while maintaining high electrical conductivity through friction stir processing (FSP). It assesses the impact of TiO 2 volume fractions and groove widths (GWs) on the wear, hardness, resistivity, and microstructure of FSPed Cu and FSPed Cu–TiO 2 surface composite. The samples obtained from the stir zone showed an increase in microhardness of the Cu–TiO 2 surface composite due to particle refinement, uniform distribution, and efficient sticking of TiO 2 with Cu. Furthermore, the wear rate increased with decreasing TiO 2 volume fractions in the composite. The worn surface microstructural analysis indicated a transition from harsh to gentle wear with increasing TiO 2 volume fractions and GWs. The average grain size reduced significantly in reinforced stir zones compared to pure Cu, and particle size decreased further with increasing groove size. Hardness increased by 25 and 50% compared to unprocessed Cu, but only a negligible increase in electrical resistivity (2.3% Ωm) after FSP.

The geopolymer mortar (GPM) prepared from industrial by-products and alkali activation solution (AAS) is one of the hot spots of current building materials. As a feasible alternative to natural river sand, manufactured sand (MS) alleviates the global ecological pressure. In this study, MS was used for fine aggregate. Sodium hydroxide (NaOH) and sodium silicate (Na 2 SiO 3 ) solution were used as AAS. Metakaolin (MK) and fly ash (FA) were used as the precursor to prepare MK-FA-based GPM with MS (MS-GPM), which was of great significance for saving non-renewable resources, mitigating the greenhouse effect, and recycling waste. Numerous studies were conducted to explore the effect of sand–precursor ratio ( r sp ) on mechanical and durability characteristics of MS-GPM. Relationships between compressive strength and tensile or flexural strength were established by linear fitting equation. Finally, analysis of variance (ANOVA) was used to systematically calculate the effect of r sp on performance. The results indicated that the mechanical strength and impermeability of MS-GPM decreased and crack resistance increased with r sp from 1 to 5. The strength of MS-GPM was the best when r sp was 1. With the increase of r sp , the proportion of MS in MS-GPM increases, and the relative cementitious material decreases, which has an adverse impact on mechanical properties and impermeability. Linear fitting revealed that the compressive strength of MS-GPM was closely related to tensile strength and flexural strength. ANOVA results indicated that r sp in the range of 1–5 had great effects on the performance of MS-GPM. The aim of this article is to further promote the possibility of applying MS-GPM in practical engineering by designing reasonable r sp .

The strength prediction of pervious concrete is hard to implement for the mix design due to the porous structure. This work studied the influence of the water-to-cement ratio on the fluidity, viscosity, and mechanical properties of cement paste. Then, the porosity, permeability, and compressive strength of the pervious concrete with various porosities were investigated, and the test results were fitted and analyzed. The result indicates that as the water-to-cement ratio increases, the viscosity of the cement paste reduces and the fluidity increases. The water-to-cement ratio has a negative linear relationship with net slurry strength. The porosity and permeability of pervious concrete fluctuate in accordance with the same rule as the water-to-cement ratio changes. The compressive strength of pervious concrete with varying design porosities increases initially, then declines as the water-to-cement ratio rises. According to the linear fitting analysis, when the water-to-cement ratio is constant, the permeability and compressive strength of pervious concrete have a positive and negative linear relationship with the design porosity, respectively. By analyzing the fitting results and combining the volume method of pervious concrete, a calculation method for mix proportion design is proposed to predict the strength of pervious concrete.

Recycled aggregate concrete (RAC) has been widely used in practical engineering construction. However, the ability of buildings to resist wind-induced vibration and earthquake effects plays an important role in building safety. It is urgent to ensure that recycled concrete still has good anti-vibration ability within the allowable strength range. By conducting damping tests on recycled concrete specimens, the results show that the damping performance of RAC is better improved compared with natural aggregate concrete. Moreover, the influence of internal factors of recycled aggregates and external environmental conditions on damping performance can be determined, and corresponding damping ratio prediction models can be constructed. However, the current prediction models still have limitations in theory and practice. The existing damping ratio prediction models have a large span of independent variables and do not consider the gradual carbonation effect in the actual environment over time. To overcome these limitations, a new damping ratio prediction model is proposed. Based on the replacement rate of recycled aggregates (RAs) and the amplitude of excitation force, the influence of modified admixtures and carbonation on damping performance is considered, and the corresponding model prediction formula is constructed. In addition, the influence mechanism is further demonstrated and explained from the macroscopic aspect of specimen profile and the microscopic aspect of electron microscopy tests. It is found that, considering both strength and cost factors, recycled concrete still has good damping performance when the replacement rate of recycled aggregates (RAs) is 40%.

As a potential replacement for traditional concrete, which has cracking and poor durability issues, self-healing concrete (SHC) has been the research subject. However, conducting lab trials can be expensive and time-consuming. Therefore, machine learning (ML)-based predictions can aid improved formulations of self-healing concrete. The aim of this work is to develop ML models that could analyze and forecast the rate of healing of the cracked area (CrA) of bacteria- and fiber-containing SHC. These models were constructed using gene expression programming (GEP) and multi-expression programming (MEP) tools. The discrepancy between expected and desired results, statistical tests, Taylor’s diagram, and R 2 values were additional metrics used to assess the constructed models. A SHapley Additive exPlanations (SHAP) approach was used to evaluate which input attributes were highly relevant. With R 2 = 0.93, MAE = 0.047, MAPE = 12.60%, and RMSE = 0.062, the GEP produced somewhat worse predictions than the MEP ( R 2 = 0.93, MAE = 0.033, MAPE = 9.60%, and RMSE = 0.044). Bacteria had an indirect (negative) relationship with the CrA of SHC, while fiber had a direct (positive) association, according to the SHAP study. The SHAP study might help researchers and companies figure out how much of each raw material is needed for SHCs. Therefore, MEP and GEP models can be used to generate and test SHC compositions based on bacteria and polymeric fibers. Graphical abstract

Nowadays, the search for unconventional antibacterial agents is very common. One of them may be eugenol (EU) (4-allyl-2-methoxyphenol), which exhibits antimicrobial properties against pathogenic bacteria and is used in the pharmaceutical industry. Owing to its structure, EU decreases the exotherm of polymerization without a negative impact on the degree of conversion. The properties of EU-modified bone cement, such as doughing time, maximum temperature, and setting time, will be characterized, as well as mechanical properties, EU release, and antibacterial properties. Bone cements were synthesized by mixing a powder phase composed of two commercially available methacrylate copolymers (Evonic) and a liquid phase containing 2-hydroxyethyl methacrylate, methyl methacrylate, triethylene glycol dimethacrylate, and EU with an amount of 0.5 wt% of bone cement sample. As an initiating system, benzoyl peroxide and N , N -dimethylaniline were used. Samples were prepared with various amounts of the initiating system. The doughing time, maximum temperature ( T max ), setting temperature ( T set ), setting time ( t set ), and compressive strength tests were determined according to the ISO 5833:2002 standard requirements. The doughing time for bone cement depends on the amount of the initiating system. The maximum temperature during curing of bone cement is very low; however, the setting time is closer to the upper limit set by the standard. The compressive strength of the tested materials is good and significantly exceeds the requirements of the standard. EU release was very high and ranged from around 43–62% after 168 h. Moreover, antibacterial studies show that the tested bone cements are bacteriostatic for Staphylococcus aureus or and Escherichia coil strains. In summary, modified bone cements meet the ISO 5833:2002 standard requirements in all parameters and are characterized by good mechanical properties (similar to or higher than commercial bone cement), high EU release, and bacteriostatic properties.

In recent years, HRB400 and HTRB600 steel bars have become the mainstream standard reinforcing steel used in concrete structures in China. However, significant controversy still exists regarding the selection of material constitutive models and the determination of model parameters for buckling, fatigue, hysteresis, and other material characteristics. In this article, an automated process of multi-parameter calculation of the constitutive model for reinforcing steel – simulation accuracy evaluation of the constitutive model – selection of the constitutive model of reinforcing steel is established based on the hybrid programming method using MATLAB and OpenSees software. First, tensile and low-cycle fatigue tests were carried out on HRB400 and HTRB600 steel bars. Second, based on the constitutive model in OpenSees software and the skeleton curve and characteristics such as yielding, fatigue, and hysteresis, the constitutive model parameters of HRB400 and HTRB600 steel bars are determined using indirect and direct fitting methods. Finally, the five similarity parameters of the simulated normalized cumulative hysteretic energy dissipation coefficient are compared with the test results. The results indicate that the simulation accuracy of the Reinforcing Steel model exceeds 72%, which is higher than other four models, making it the best choice for reinforcing steel in numerical simulation.

Fe 3+ -activated near-infrared (NIR) luminescent materials have attracted widespread attention due to their tunable emission wavelength and extensive applications in various fields such as plant growth, food analysis, biomedical imaging, and night vision. Many excellent NIR materials have been developed by introducing non-toxic and environmentally friendly Fe 3+ ions into different inorganic hosts. This article elucidates the luminescent properties of Fe 3+ ions by combining the Tanabe–Sugano energy level diagram and the configuration coordinate model. The latest research progress on Fe 3+ -doped NIR luminescent materials is outlined, summarizing the luminescent characteristics of various Fe 3+ -doped materials, including emission wavelength, emission bandwidth, quantum efficiency, and thermal stability. Particularly, a detailed summary and analysis of the application areas of Fe 3+ -doped NIR luminescent materials are provided. Finally, the future prospects and challenges faced by Fe 3+ -doped NIR luminescent materials are presented. This review contributes to a deeper understanding of the luminescence mechanism of Fe 3+ and the research progress of iron ion-doped luminescent materials, aiming to develop advanced Fe 3+ -activated NIR luminescent materials with enhanced performance and explore new application fields.

Grain-preferred orientation significantly influences the brittle fracture mechanism and failure mode of crystalline rocks. However, current grain-based models (GBMs) based on particle flow code (PFC) software are mostly proposed on the basis of the Voronoi tessellation method for grain boundary generation, which is difficult to simulate the heterogeneity of microstructure such as shape and orientation of rock minerals. To study the effect of grain-preferred orientation on macroscopic mechanical properties and microscopic characteristics of crystalline rocks, a novel grain-based microstructure transformation method (MTM) is proposed. Based on the MTM, a GBM with a target aspect ratio and crystal orientation is obtained by transforming the Voronoi crystal geometry through a planar coordinate mapping. Specifically, embedded FISH language is used to control random mineral seed size and distribution pattern to generate Tyson polygons. A polygon geometry that satisfies the rock texture is obtained as a grain boundary by spatially transforming the vertex of the Tyson polygon. The transformed complex geometry is taken as the crystal structure of the GBM, and the Lac du Bonnet granite models with different aspect ratios and crystal orientations were developed in PFC 2D . Finally, a series of unconfined compressive strength tests are performed in PFC 2D to verify the proposed modeling methods for the geometric variation of the crystals and to study the effects of the preferred orientation of the grains on the macroscopic mechanical properties and microscopic fracture mechanisms of the crystalline rocks from different perspectives.

Multilayer adhesive bonded structures/materials (MABS) are widely used as structural components, especially in the field of aerospace. However, for MABS workpieces, the facts that the weak echo of the deep interfacial debonding defects (DB) caused by the large acoustic attenuation coefficient of each layer and this echo, which generally aliases with the excitation wave and the backwall echo of the surface layer, pose a great challenge for the conventional longitudinal wave ultrasonic nondestructive testing methods. In this work, an ultrasonic resonance evaluation method for deep interfacial DBs of MABS is proposed based on the ultrasonic resonance theory and the aliasing effect of ultrasonic waves in MABS. Theoretical and simulation analysis show that the optimal inspection frequency for II-interfacial DBs is 500 kHz when the shell thickness is 1.5 mm and the ethylene propylene diene monomer (EPDM) thickness is 1.5 mm, and the optimal inspection frequency is 250 kHz when the shell thickness is 1.5 or 2.0 mm and the EPDM thickness is 2.0 mm. Verification experiments show that the presence of a DB in the II-interface causes a resonance effect, and in the same inspection configuration, the larger the defect size, the more pronounced this effect is. This resonance effect manifests itself as an increase in the amplitude and an increase in the vibration time of the A-scan signal as well as a pronounced change in the frequency of the received ultrasonic wave. In addition, the increase in the excitation voltage further highlights the ultrasonic resonance effect. Four imaging methods – the integrations of the signal and the signal envelope curve, the maximum amplitude of the fast Fourier transform (FFT) of the signal, and the signal energy – were used for C-scan imaging of ultrasonic resonance evaluation of MABS’s deep interfacial DBs and all these methods can clearly show the sizes and locations of the artificial defects and internal natural defect. The normalized C-scan imaging method proposed in this study can further highlight the weak changes in the signals in the C-scan image. The research results of this study have laid a solid theoretical and practical foundation for the ultrasonic resonance evaluation of MABS.

The use of titanium gypsum instead of gypsum as a raw material for the preparation of gypsum-slag cementitious materials (GSCM) can reduce the cost and improve the utilization of solid waste. However, titanium gypsum contains impurities such as Fe 2 O 3 , MgO, and TiO 2 , which make its effect on the performance of GSCM uncertain. To investigate this issue, GSCM doped with different ratios of Fe 2 O 3 , MgO, and TiO 2 were prepared in this study, the setting time and the strength of GSCM at 3, 7, and 28 days were tested. The effects of different oxides on the performance of GSCM were also investigated by scanning electron microscopy, energy spectrum analysis, X-ray diffraction analysis, and thermogravimetric analysis. The experimental results showed that Fe 2 O 3 , MgO, and TiO 2 all had a certain procoagulant effect on GSCM and a slight effect on the strength. Through micro-analysis, it was found that the main hydration products of GSCM were AFt phase and calcium–alumina–silicate–hydrate (C–(A)–S–H) gels. Fe-rich C–(A)–S–H gels were observed with the addition of Fe 2 O 3 , and Mg(OH) 2 and M–S–H gels were observed with the addition of MgO. The addition of TiO 2 did not result in new hydration products from GSCM.

In recent years, there has been an increase in accidents involving vessels colliding with bridge piers. These ship–bridge collisions can result in tragic loss of life and severe damage to the bridge structure. To address this issue, a type of fender pile made of winding-formed glass fiber-reinforced polymer (GFRP) was proposed as a solution. In this article, three- and four-point bending tests were performed to compare and analyze the damage modes and load-carrying capacity of the fender piles at two different winding angles, namely 45° and 75°. Vertical impact test was simulated using ANSYS/LS-DYNA to verify finite element models. The results revealed variations in damage patterns and bending performance of GFRP piles under the two fiber winding angles. The simulation results suggest that GFRP fender piles can effectively increase the impact time of ship–bridge collisions and reduce the collision forces, thereby significantly improving the protection of bridge piers.

In industry, synthetic fibre reinforcements are popular due to their cost-effectiveness and lightweight nature. However, the non-reusability and non-degradability have raised environmental concerns and prompted scientists to explore more environmentally friendly alternatives. Natural fibres are being investigated as potential replacements to address these issues and promote sustainability. This study investigated the effect of fibre loading and orientation on the heat conductivity of polymer resins using a finite element-based numerical model developed in our previous research. The numerical analysis was conducted in ANSYS® modelling and simulation using glass and sisal fibres in combination with three distinct matrix materials (epoxy, polyester, and vinyl ester). Different orientations (parallel, perpendicular, 45°, and normal) and volume of fibre fractions (20–35%) were used for the analysis. The properties of the materials were incorporated into the ANSYS Engineering database, and the composite model was divided into five segments to analyse the heat transfer. The thermal boundary condition was implemented by keeping one side of the cylinder at 120°C. The results showed that the thermal conductivity of the composites decreased as the volume fraction of natural fibres increased. Epoxy-based composites exhibited better insulation performance than polyester and vinyl ester-based composites. This study demonstrated the potential of using natural fibres to improve the thermal insulation properties of composites.

Using an easy mechanical agitation process at room temperature, a metal–organic framework (MOF) based on metallic Zn( ii ), organic linker benzene-1,3,5-tricarboxylic acid (Zn-BTC), Fe 3 O 4 nanoparticles, and nanocellulose are combined to create a novel composite material called Fe 3 O 4 /NC/MOF. Various tools were used to characterize the created composite. Congo red, Basic Blue 54 (BB 54), Basic Violet 14 (BV 14), and Acid red 88 (AR 88) dyes were effectively eliminated from water using Fe 3 O 4 /NC/MOF. A number of variables were investigated, including pH, temperature, contact time, initial dye concentration, and adsorbent dosage. To understand the specific adsorption process, a number of kinetic models were used, including the intra-particle diffusion model, Elovich’s kinetic model, pseudo-first-order, and pseudo-second-order kinetic models. The most accurate description of dye sorption kinetics comes from the pseudo-second-order kinetic model. Also, the Langmuir model is more accurate to describe isotherms than Freundlich and Temkin models. Furthermore, thermodynamic parameters were obtained and examined, including enthalpy (Δ H ), Gibbs free energy (Δ G ), and entropy (Δ S ). After four cycles, the Fe 3 O 4 /NC/MOF demonstrated good recyclability. According to experimental research, this adsorbent is promising to enhance the quality of environmental water that has been tainted with organic dyes.

In this study, the mechanical properties of non-crimp fabric (NCF) composite laminates under low-velocity impact and compression after impact (CAI) tests were studied by Scanning electron microscopy (SEM) and Digital image correlation (DIC) techniques. The impact response under different impact times, impact angles, and impact distance is studied. Similarly, in CAI test, DIC technique is used to reveal the whole process of NCF composite compression failure, and SEM is used to reveal the microscopic failure form. The experimental results show that the impact damage process of NCF composites has strong directivity. The concrete manifestation is that the internal failure will extend along the paving direction at the failure layer. The peak load generated under 20 J impact energy is about 1/2 of that under 40 J impact energy. The impact distance is one of the important factors affecting the coupling effect of multiple impacts, and the impact angle has little effect on the internal damage extension. The proportion of internal damage area also supports the relevant view, that is, the average difference in the proportion of internal damage area under different impact distance is about 5%, while the average difference in the proportion of internal damage area under different impact angles is about 3%. During the compression process, the main failure mode is shear failure and the failure mode is brittle fracture. The oblique fracture occurs only when the oblique is 45° and the impact distance is large (50 mm). The impact angle has little effect on the residual compression performance of NCF.

To tackle the challenge of dislocation damage when tunnels traverse active fault zones, this study introduces the concept of using brittle buffer materials for anti-dislocation. Building on this concept, we propose a novel concrete buffer material utilizing large-sized spherical super absorbent polymers (SAP) as a porogen, aimed at ensuring the safety of tunnel structures during active fault dislocations. To investigate the feasibility and superiority of SAP concrete as a buffer material compared to other similar materials, we prepared samples with three different SAP concrete proportions and conducted a series of physical and mechanical tests. The results show that SAP pre-hydrated with 0.2 mol·L −1 sodium carbonate solution exhibits a slower rate of moisture loss in the cement slurry, aiding the hydration reaction of concrete. The permeability coefficient of SAP concrete is approximately 10 −7  cm·s −1 , slightly lower than foam concrete of the same density level. SAP concrete buffer material demonstrates significant brittleness, in contrast to the mostly ductile nature of other buffers such as foam concrete and rubberized concrete. Utilizing the brittle nature of SAP concrete materials, when applied to tunnels affected by stick–slip active fault dislocations, its instantaneous loss of compressive capacity provides excellent yield performance, thus protecting the tunnel lining from damage. However, under certain circumferential pressure conditions, both the peak and residual strength of SAP concrete significantly increase. High peak and residual strengths do not favor the effective buffering effect of SAP concrete; therefore, an approach involving the intermittent arrangement of precast buffer blocks has been proposed for application.

Using artificial intelligence-based tools, this research aims to establish a direct correlation between the alkali-activated concrete (AAC) mix design factors and their performances. More specifically, the machine learning system was fed new property data obtained from AAC mixes used in laboratory experiments. The rheological parameters (yield stress [static/dynamic] and plastic viscosity) of AAC were predicted using the multilayer perceptron neural network (MLPNN) and bagging ensemble (BE) models. In addition, the R 2 values, k-fold analyses, statistical checks, and the dissimilarity between the experimental and predicted compressive strength were employed to assess the performance of the created models. Also, the SHapley additive exPlanation (SHAP) approach was used for examining the relevance of influencing parameters. The BE approach was found to be significantly accurate in all prediction models, with R 2 greater than 0.90, and MLPNN models were found to be moderately precise, with R 2 slightly below 0.90. However, the error assessment through statistical checks and k-fold analysis also validated the higher precision of BE models over the MLPNN models. Building models that can calculate rheological properties of AAC for different values of input parameters could save a lot of time and money compared to doing the tests in a laboratory. In order to ascertain the required amounts of raw materials of AAC, investigators, as well as businesses, may find the SHAP study helpful. Graphical abstract

The utilization of waste glass with micro- and nanoparticles in ultra-high-performance concrete (UHPC) has garnered significant interest due to its potential to enhance sustainability and material performance. This study focuses on the implications of integrating microwaste glass (MG) and nanowaste glass in the presence of waste foundry sand and its impact on the properties of UHPC. The particular emphasis of the current work is on compressive strength, tensile strength, sorptivity, and microstructure. It is found that MG enhances compressive strength, decreased tensile strength, reduced sorptivity, and a more compact microstructure. The results indicate that replacing cement with 20% microglass achieves the optimal compressive strength by increasing up to 11.6% at 7 days, 9.5% at 28 days, and 10.18% at 56 days. Nanowaste glass, owing to its increased reactivity and larger surface area, accelerates calcium silicate hydrate formation and improves compressive strength. At the same time, the effective utilization of nanowaste glass improves long-term resilience with an optimum compressive strength at 1.5% replacement ratios of 17.5, 18.9, and 16% at 7, 28, and 56 days, respectively. Splitting tensile strength increased by 16% at 20% MG and 21% at 1.5% nanowaste glass, respectively. Utilizing MG and nanowaste glass in UHPC with waste foundry sand is a promising method for boosting material performance and minimizing environmental impact.

Adhesive bonds are frequently used in industries such as aerospace, automotive, and civil engineering due to their ability to reduce damage to the adherend and their lightweight. However, their application is restricted by their inadequate durability and reliability in hostile environments. Graphene nanoplatelets (GNPs) are employed to enhance epoxy adhesives in this article. The thick adherend shear test is utilized to examine how the shear properties change with different water ageing times. Before exposure to water ageing conditions, GNP-reinforced adhesives exhibit a 3.51% increase compared with neat epoxy at a GNP content of 0.25 wt%. However, after 56 days of water ageing, the increase in shear strength is found to be 13.79%. This suggests that the well-dispersed GNP can reduce the degradation rate in shear properties by half, from 16.71 to 8.44%, at a GNP content of 0.25 wt%. Additionally, as water ageing time increases, the positive influence of GNP on shear properties becomes more evident. The addition of GNP delays the degradation of shear properties caused by water ageing conditions. The effect of GNP does not improve with higher GNP content. When the GNP contents increase to 1 wt%, the shear strength of the GNP-reinforced adhesive decreases compared to neat epoxy.

In this study, unbalanced direct current magnetron sputtering was employed to develop TiBCN coatings on Si (100) wafers. The carbon (C) concentration was varied to manipulate the phase structure and mechanical properties of the coatings. The coatings were analyzed using Raman spectroscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and nanoindentation. The results revealed that the TiBCN-2 coating, with a C concentration of 4.4 at.%, exhibited optimal hardness and elastic modulus values of 33 and 291 GPa, respectively. On the other hand, as the C content increased from 4.4 to 24.4 at.%, the hardness and elastic modulus values of the coatings decreased to 21 and 225 GPa, respectively, due to the formation of boron nitride and carbon phases within the coating matrix. Therefore, the inclusion of an ideal C concentration can considerably improve the properties of TiBCN coatings, thus rendering the coating a desirable material for cutting tools.

This research focuses on the aging resistance properties of asphalt, which are crucial for determining the lifespan of asphalt pavement. To combat aging, waste tire pyrolysis oil (TPO) is often added to asphalt, enhancing its resistance to aging but compromising high-temperature performance. This study offered a pioneering solution by integrating TPO with polyphosphoric acid (PPA) to address these issues. In this study, we conducted a series of tests to characterize the properties of PPA/TPO modified asphalt, including temperature sweep and bending beam rheometer tests. The results demonstrated that the presence of PPA in the PPA/TPO modified asphalt could improve its high-temperature performance while maintaining its low-temperature properties. Moreover, PPA in the PPA/TPO modified asphalt enhanced the modified asphalt’s resistance to fatigue and deformation during the aging process, while the presence of TPO effectively reduced the impact of thermo-oxidative aging on the modified asphalt during the aging process. Additionally, physicochemical interactions between the base asphalt and modifiers were observed before and after aging. In summary, this study had offered an innovative method to enhance the anti-aging properties of asphalt, and had provided more options for sustainable, environmentally friendly roads.

Microbial exopolysaccharides (EPSs) are gaining interest as alternatives to chemical antioxidants and pharmaceuticals. This study mines the promising biomedical and antimicrobial potential of a marine bacterium, a prolific EPS producer, isolated from the Red Sea. Pseudomonas sp. strain AHG22 generated an EPS weighing 6.98 g·L −1 , coded EPSF8, subjected to FT-IR and HPLC chemical analysis. EPSF8 was then investigated for antioxidant assessment by 2,2-diphenyl-1-picrylhydrazyl (DPPH), H 2 O 2 , ABTS˙ + , nitric oxide, total antioxidant capacity (TAC), and ferric reducing antioxidant power (FRAP). EPSF8 had an IC 50 of 46.99 μg·mL −1 in the DPPH antioxidant assay and antioxidant capacities of 219.45 μg·mg −1 ascorbic acid equivalent (AAE) in the TAC assay and 54.15 μg·mg −1 AAE in the FRAP assay. The in vitro anti-inflammatory effect of EPSF8 was tested against 5-lipoxygenase (5-LOX) and cyclooxygenase-2 (COX-2) enzymes and compared with the drugs ibuprofen and celecoxib used as controls. The IC 50 values of 5-LOX, COX-2, ibuprofen, and celecoxib were found to be 14.82, 15.49, 1.5, and 0.28 μg·mL −1 , respectively. Additionally, EPSF8 revealed antidiabetic activity toward α-amylase and α-glucosidase, and the IC 50 values were 93.1 and 127.28 μg·mL −1 , compared to those of acarbose (50.93 and 4.13 μg·mL −1 , respectively). Anti-obesity activity of EPSF8 by lipase inhibition revealed IC 50 = 56.12 μg·mL −1 compared to orlistat (IC 50 = 20.08 μg·mL −1 ) as a control. EPSF8 displayed antibiofilm and bactericidal activity against Gram-positive (G +ve) and Gram-negative (G −ve) ATCC pathogenic bacterial strains. It had a minimum bactericidal concentration/minimum inhibitory concentration ratio ≤2, indicating a broad bactericidal spectrum. Furthermore, EPSF8 is evidenced to have a promising anti-butyrylcholinesterase activity for the control of Alzheimer’s disease. The findings of the present analysis suggest that the isolated Pseudomonas sp. strain AHG22 EPS can potentially be explored as a promising green therapeutic compound.

The number of studies aimed at the characterization of reinforced lime-based mortars for use in the rehabilitation of historic buildings is still very small. This fact contrasts with the growing interest of the industry in these products as substitutes for cement mortars, both for their constructive advantages (compatibility requirements) and their lower cost (economic and environmental). For this reason, this study investigates the effect of basalt fiber length on the physical, mechanical, and durability properties of reinforced natural hydraulic lime mortars and provides criteria for selecting optical blends to meet the various performance requirements for their use as building materials for traditional and contemporary structures. Specimens with 1% volume of basalt fibers and lengths of 6, 12, 18, and 24 mm have been tested. The results in fresh mortar show that increasing the fiber length decreases the consistency and bulk density, as well as increases the air content. Regarding the durability properties of hardened mortar, no direct relationship is observed between fiber length and the decrease in the water absorption coefficient of reinforced mortars. Nor is there a clear relationship between fiber length and the increase in Shore hardness and the decrease in adhesive strength in the reinforced mortars. On the contrary, for small lengths (up to 12 mm), there is a direct relationship between fiber length and the increase in other fundamental mechanical properties such as flexural and compressive strength. Based on the results obtained, a predictive model is proposed to determine the amplification factor of flexural and compressive strength as a function of fiber length.

A composite-modified asphalt was developed by incorporating tire pyrolytic carbon black (TPCB) with a silane coupling agent (SCA) to enhance its ductility and storage stability. The functional binding between asphalt and TPCB was improved by the addition of SCA. The gray correlation comprehensive evaluation method is incorporated into the response surface methodology (RSM), leading to an improved RSM. The improved RSM was employed to optimize the content of the modifier and the preparation process to enhance overall performance. A central composite design-based experiment was conducted to optimize the penetration, softening point, 10°C ductility, Brookfield rotational viscosity, and storage stability indicators of modified asphalt. The response surface of the gray comprehensive evaluation value of the evaluation indicators was calculated using the gray correlation analysis method, and a second-order regression model was established between independent variables such as TPCB, SCA content, and shear time factor and the gray comprehensive evaluation value. This model analyzed the impact of a single variable and variable interaction on the performance of the TPCB/SCA composite-modified asphalt. The optimized model results showed that the preparation parameters that optimize the expected comprehensive performance of the composite-modified asphalt are 9.2% TPCB content, 2.1% SCA content, and a shear time of 56.3 min. Finally, the TPCB/SCA composite-modified asphalt prepared with the improved RSM exhibited the highest gray comprehensive evaluation value and the best overall performance, indicating the feasibility of the optimized preparation parameters with the improved RSM.

Marble cement (MC) is a new binding material for concrete, and the strength assessment of the resulting materials is the subject of this investigation. MC was tested in combination with rice husk ash (RHA) and fly ash (FA) to uncover its full potential. Machine learning (ML) algorithms can help with the formulation of better MC-based concrete. ML models that could predict the compressive strength (CS) of MC-based concrete that contained FA and RHA were built. Gene expression programming (GEP) and multi-expression programming (MEP) were used to build these models. Additionally, models were evaluated by calculating R 2 values, carrying out statistical tests, creating Taylor’s diagram, and comparing theoretical and experimental readings. When comparing the MEP and GEP models, MEP yielded a slightly better-fitted model and better prediction performance ( R 2 = 0.96, mean absolute error = 0.646, root mean square error = 0.900, and Nash–Sutcliffe efficiency = 0.960). According to the sensitivity analysis, the prediction of CS was most affected by curing age and MC content, then by FA and RHA contents. Incorporating waste materials such as marble powder, RHA, and FA into building materials can help reduce environmental impacts and encourage sustainable development.

Recently, experts have become particularly interested in the treatment of disorders caused by magnesium shortage. Hypomagnesemia is produced by a magnesium deficit in the blood, which is an additional stimulation for different diseases such as vomiting, drowsiness, nausea, loss of appetite, and so on. To compensate for this shortage, magnesium is injected as a nanoparticle in the blood (base fluid). The properties of these magnesium nanoparticles specifically their size, dispersion, and surface characteristics are crucial for optimizing their bioavailability and therapeutic efficacy. Advanced material characterization techniques ensure the stability and enhanced performance of these nanoparticles in the physiological environment. Based on these applications, the current research aims to address magnesium deficiency via Powell–Eyring nanofluid flow distorted by the linearly stretchable sheet in the region of the stagnation point. Linear thermal stratification, viscous dissipation, and Joule heating are used to reveal the heat transport features. The magnetic field is applied to the nanofluid at an angle α to further control the fluid dynamics and nanoparticle behavior. Transformations are used to create a set of dimensionless governing equations. Comparative graphs are used to explain the physical behaviors of temperature and velocity fields, demonstrating how material properties impact fluid dynamics. The well-known convergence method (homotopy analysis method) is used to solve the model by comparing graphs.

Monitoring the stress of steel strands, from initial tension to eventual failure, is paramount for assessing structural safety and understanding its failure mechanism. Current monitoring methods are restricted in measuring stress only until yielding because of their limited range. This study proposes a novel coaxial strain-sensing cable (CSSC) based intelligent steel strand (CSSC-ISS), which has both functions of force-bearing and self-sensing. First, the prototype design of CSSC-ISS and the sensing principle of CSSC are introduced. Then, a fabrication method of small-diameter CSSC is proposed, which is then encapsulated with glass fiber reinforced polymer (GFRP) material, forming a GFRP sensing rod (GFRP-SR). The next step involves replacing the strand’s central wire with the GFRP-SR, culminating in the creation of the CSSC-ISS. Finally, Laboratory tests show that the CSSC has excellent strain-sensing performance with a resolution of at least 100 µε and a measurement range of 150,000 µε. The GFRP-SR offers good sensing potential and comparable mechanical strength to standard GFRP rods. Notably, the CSSC-ISS could measure stress up to strand failure, retaining 87.9% tensile strength and 88.7% elastic modulus compared to standard steel strands. It is verified that the CSSC-ISS can consistently measure its stress condition throughout its life cycle without compromising its load-bearing potential.

Geopolymer concrete (GPC) serves as an environmentally conscious alternative to traditional concrete, offering a sustainable solution for construction needs. The ability to make on-site changes is dependent on the concrete’s strength after casting, which must be higher than the target value. To anticipate the concrete’s strength before it is poured is, thus, quite helpful. Three ensemble machine learning (ML) approaches, including gradient boosting, AdaBoost regressor, and extreme gradient boosting, are presented in this work as potential methods for forecasting GPC’s mechanical strength that incorporates corncob ash. To determine which modeling parameters are crucial, sensitivity analysis was employed. When the compressive strength and split-tensile strength of GPC were tested with ensemble ML models, R 2 values of more than 90% were discovered between the predicted and actual results. Statistics and a k -fold analysis based on the error and coefficient of determination were used to verify the developed models. Slag amount, curing age, and fine aggregate quantity were the three mix proportions that had the most impact on GPC’s mechanical strength, as shown in the sensitivity analysis. The results of this study demonstrated that ensemble boosting approaches could reliably estimate GPC mechanical strength. Incorporating such procedures into GPC quality control can yield significant improvements. Graphical abstract

Due to the uncertainty of trauma or infection, customized bone substitutes are often required in clinic. Meanwhile, excessive use of antibiotics may lead to drug resistance. Therefore, the design of anti-infection bone tissue engineering scaffold is of very important. In this study, porous titanium alloy bone tissue engineering scaffolds were designed and fabricated by 3D printing. TiO 2 nanotubes were further constructed on the scaffolds through electrochemical anodic oxidation, achieving the drug loading and anti-infection functions. The micron-level bionic pores were fabricated by the 3D printing process, and the secondary nanoscale-level nanotubes were achieved through the anodic oxidation process. Thereafter, the micro–nano structured porous bone tissue engineering scaffolds are presented. This structure features that the drug release rate can be regulated by loading the anti-infection drug minocycline and coating them with poly(lactic- co -glycolic acid) (PLGA) in the nanotubes. According to the results, the micro–nano composite porous scaffold showed uniform and controllable micro–nano pores, it may load anti-infection drugs and shown anti-infection ability. In addition, the PLGA coating may delay the drug release and maintain a sustained anti-infection function for the scaffold in a week. This study provides new ideas for designing antibacterial bone tissue engineering scaffold.

Superhydrophobic nanostructured coatings are a promising technology in construction engineering. This study developed a hydrophobic film through a simple mixing method, utilizing kaolin and polytetrafluoroethylene as additive particles, 1 H ,1 H ,2 H ,2 H -perfluoro-decyl triethoxysilane as a modifier, and epoxide resi n and polyamide curing agent as adhesives. By controlling variables, it was determined that the C 1 P 0.2 EP coating immersed in a 3.5 wt% NaCl solution for 1, 3, and 7 days exhibited the maximum impedance radii of 47,373, 20,334, and 1,982 Ω·cm 2 , respectively. It also demonstrated the highest Bode modulus values, the largest E corr , and the smallest I corr . Furthermore, after 300 h in a salt spray chamber with a 3.5 wt% NaCl solution, the C 1 P 0.2 EP coating showed no rust spots or bubbles, demonstrating its excellent corrosion resistance. Moreover, wear resistance tests and self-cleaning experiments were conducted on the C 1 P 0.2 EP coating. The results showed that after 100 friction cycles, the surface exhibited no visible scratches, and the contact angle of the coating decreased by only 4°. Additionally, neither soil particles nor dirty water adhered to the coating, indicating that the C 1 P 0.2 EP hydrophobic coating possesses not only excellent corrosion resistance but also superior wear resistance and self-cleaning capabilities.

High-entropy alloy (HEA) coatings have demonstrated great potential in anti-wear applications. To further improve the mechanical and tribo-corrosion properties of the HEA coatings, the VAlTiMoSi, (VAlTiMoSi) 80 C 20 , and (VAlTiMoSi) 60 C 40 coatings were successfully deposited by DC magnetron sputtering. The microstructure, mechanical, and tribo-corrosion properties of as-deposited and heat-treated coatings were analyzed. All the as-deposited HEA coatings were BCC + amorphous phases. The thermal effect promoted the formation of intermetallic compounds, and the C inhibited the formation of Mo 3 Si and Ti 5 Si 4 . The hardness and elastic modulus of the heat-treated VAlTiMoSi coating were 20.1 and 294.0 GPa, respectively. The heat-treated (VAlTiMoSi) 60 C 40 coating showed the lowest wear rate, namely 5.2 × 10 −14  m 3 ·Nm −1 , and the best formation ability of passive film in 3.5 wt% NaCl solution.

Investigating the damage degradation of rock during the freezing and thawing process is more consistent with the actual engineering environment, considering its internal initial damage. In this study, the effects of initial damage from preloading and subzero-temperature freezing–thawing on microscopic and macroscopic mechanical properties of sandstone were studied based on the nuclear magnetic resonance (NMR) technique. The results show that the P-wave velocity of the sample decreased, while the porosity increased as the initial damage level increased. The distribution of T 2 signal intensity exposed to the low-temperature freezing–thawing–saturation treatment was rather larger than that under normal temperature conditions for samples with different levels of initial damage from preloading, indicating that the low-temperature freezing–thawing condition would promote the porosity and have an obvious increase in damage. A continuum damage model considering subzero-temperature freezing–thawing damage from different pore sizes was finally introduced to describe the damage evolution mechanism of sandstone. The research results can be used to quantitatively evaluate the damage evolution mechanism of sandstone treated by subzero-temperature freezing–thawing without mechanical tests. Furthermore, the analysis and research results show that the damage variables of sandstone obtained by the NMR theory were lower than those of classical rock mechanics theory.

In place of Portland cement concrete, alkali-activated materials (AAMs) are becoming more popular because of their widespread use and low environmental effects. Unfortunately, reliable property predictions have been impeded by the restrictions of conventional materials science methods and the large compositional variability of AAMs. A support vector machine (SVM), a bagging regressor (BR), and a random forest regressor (RFR) were among the machine learning models developed in this study to assess the compressive strength (CS) of AAMs in an effort to gain an answer to this topic. Improving predictions in this crucial area was the goal of this study, which used a large dataset with 381 points and eight input factors. Also, the relevance of contributing components was assessed using a shapley additive explanations (SHAP) approach. In terms of predicting AAMs CS, RFR outperformed BR and SVM. Compared to the RFR model’s 0.96 R 2 , the SVM and BR models’ R 2 -values were 0.89 and 0.93, respectively. In addition, the RFR model’s greater accuracy was indicated by an average absolute error value of 4.08 MPa compared to the SVM’s 6.80 MPa and the BR’s 5.83 MPa, which provided further proof of their validity. According to the outcomes of the SHAP research, the two factors that contributed the most beneficially to the strength were aggregate volumetric ratio and reactivity. The factors that contributed the most negatively were specific surface area, silicate modulus, and sodium hydroxide concentration. Using the produced models to find the CS of AAMs for various input parameter values can help cut down on costly and time-consuming laboratory testing. In order to find the best amounts of raw materials for AAMs, academics and industries could find this SHAP study useful.

This work examines the behaviour of flow and heat transmission in the presence of hybrid nanofluid in thermal radiation, heat generation, and magnetohydrodynamics. The hybrid state in this model is represented by two different fluids, TiO 2 (titanium dioxide) and Ag (silver). The enclosure is wavy and slanted, with curving walls on the left and right. The finite difference approximation method was utilized to resolve the fundamental equations after they were non-dimensionalized, which are further reduced to a fourth-order bi-harmonic equation and are numerically solved based on the biconjugate gradient-stabilized approach method. The simulations are performed with various Rayleigh numbers, Hartmann numbers, an inclination angle of the enclosure, radiation parameters, heat generation parameters, inclination angle of the magnetic field, and volume fraction of hybrid nanoparticles. The streamlines, isotherms, and average Nusselt number contours are used to depict the thermo-fluid patterns. The findings show that the average Nusselt number relies on ϕ and increases as ϕ rises. The investigation’s findings demonstrated that the transfer of heat on the heated bottom wall significantly increases with the Rayleigh number (Ra = 10 5 and 10 6 ). At a cavity inclination of 45°, interesting multi-vortex structures are observed. The results of this study may enhance the effectiveness of solar collectors, heat exchangers, and other similar systems that depend on convective heat transfer in nature.

Friction stir welding (FSW) is increasingly utilized in aerospace for welding dissimilar Al–Mg alloys without melting, overcoming fusion welding challenges. This summary highlights FSW’s key aspects for dissimilar Al–Mg alloys and its aerospace relevance. These alloys are widely used in aerospace due to their beneficial properties, but fusion welding faces issues like brittle intermetallic compounds (IMC) and decreased mechanical properties. FSW addresses these challenges by using a rotating tool to generate frictional heat, plasticizing the material for solid-state joining without melting. This reduces IMC formation, enhancing joint strength and mechanical properties. Critical parameters like rotational speed, traverse speed, tool design, and process variables are emphasized for optimal FSW of dissimilar Al–Mg alloys. Joining these alloys is crucial in aerospace for applications such as aircraft structures, engine components, and fuel tanks. FSW offers advantages like weight reduction, improved fuel efficiency, and structural integrity enhancement. It allows welding dissimilar Al–Mg alloys with varying compositions for tailored material combinations meeting specific needs. In conclusion, FSW of dissimilar aluminum alloys is promising for aerospace, creating defect-free joints with improved mechanical properties. However, further research is needed to optimize parameters, explore tool designs, and validate long-term performance in aerospace environments. Graphical abstract

Fe nanoparticle-functionalized ordered mesoporous carbon (Fe 0 /OMC) was synthesized using triblock copolymers as templates and through solvent evaporation self-assembly, followed by a carbothermal reduction. Fe 0 /OMC had three microstructures of two-dimensional hexagonal (space group, p6mm, Fe 0 /OMC-1), body centered cubic (Im3̄m, Fe 0 /OMC-2), and face centered cubic (Fm3̄m, Fe 0 /OMC-3) which were controlled by simply adjusting the template. All Fe 0 /OMC displayed paramagnetic characteristics, with a maximum saturation magnetization of 50.1 emu·g −1 . This high magnetization is advantageous for the swift extraction of the adsorbent from the solution following the adsorption process. Fe 0 /OMC was used as an adsorbent for the removal of silver ions (Ag( i )) from aqueous solutions, and the adsorption capacity of Fe 0 /OMC-1 was enhanced by the functionalization of Fe 0 . Adsorption property of Fe 0 /OMC-1 was significantly higher than that of Fe 0 /OMC-2 and Fe 0 /OMC-3, indicating that the long and straight ordered pore channels were more favorable for adsorption, and the adsorption capacity of Ag( i ) on Fe 0 /OMC-1 was 233 mg·g −1 . The adsorption process exhibited conformity with both the pseudo-second-order kinetic model and the Freundlich model, suggesting that the dominant mechanism of adsorption involved multilayer adsorption on heterogeneous surfaces.

With the continuous upgrading of infrastructure construction and the gradual development of theoretical research about engineering construction, higher performance requirements have been put forward for concrete materials. Therefore, to meet the engineering quality requirements of various concrete structures, the research direction of engineering materials has shifted towards developing new concrete with high strength, high ductility, high toughness, and other multifunctional properties. Mixing two or more types of fibers with conductive properties with the cement matrix material allows various fibers to leverage their strengths and weaknesses, thereby utilizing their respective characteristics. This results in the formation of a complex-phase conductive fiber cementitious material (CFCM), which enhances the safety, durability, and toughness of the structure. It enables the engineering structure to exhibit intelligence and resourcefulness, thereby improving its service life and reducing the full life cycle cost of the cementitious material structure. Additionally, this approach relatively eases the demand for concrete materials and reduces material consumption. This method represents one of the research directions for new concrete. Complex-phase CFCMs are essentially smart materials capable of sensing not only compressive or tensile stresses but also temperature. The emergence of CFCM represents a significant step forward in enhancing the mechanics, functionality, and sustainability of modern infrastructure. In this experiment, an orthogonal test involving 16 working conditions with three factors and four levels was designed, with steel fiber (SF) type, SF content, and carbon fiber (CF) content as the factors. The study focused on the physical and mechanical properties of composite conductive fiber cement-based materials containing both SF and CF. Performance indicators such as flexural strength, volume resistivity, and energized temperature rise of the composite conductive fiber cement-based materials were tested. The analysis of orthogonal tests produced the following results regarding the degree of influence of each factor on the mechanical and physical properties: the order of influence on flexural strength was SF doping > SF type > CF doping. Further analysis revealed that the best combination was A 4 B 4 C 4. The relationship between the effect of each factor on resistivity is as follows: carbon fiber doping > SF doping > SF type. Comparing the weights between the levels, it can be observed that the optimal combination of conductivity schemes is also A 3 B 4 C 4. SF and CFs, respectively, enhanced the mechanical and physical properties of complex-phase conductive fiber cementitious materials. The results of the temperature rise test on cementitious materials concluded that there is a certain relationship between the temperature rise and electrical conductivity. Specifically, the higher the electrical conductivity, the greater the temperature rise observed. Through orthogonal analysis of electrical conductivity, disregarding the effect of the non-significant influence factor SF type on the conductive heating test, the impact of two factors, CF doping and SF doping, on the heating test was investigated under 16 sets of conditions, and the data were analyzed visually. The optimal mix ratio for the test is A 3 B 4 C 4, determined through comprehensive optimization of orthogonal and intuitive analyses. This means that the optimal physico-mechanical properties are achieved when using copper-plated SFs, with a SF dosage of 1.25% and a CF dosage of 0.48%. As a preceding study in the field of intelligent concrete, this experiment explores the research path of intelligent concrete, which holds positive significance for subsequent, more intricate research endeavors.

The cementitious composite’s resistance to the introduction of harmful ions is the primary criterion that is used to evaluate its durability. The efficacy of glass and eggshell powder in cement mortar exposed to 5% sulfuric acid solutions was investigated in this study using artificial intelligence (AI)-aided approaches. Prediction models based on AI were built using experimental datasets with multi-expression programming (MEP) and gene expression programming (GEP) to forecast the percentage decrease in compressive strength (CS) after acid exposure. Furthermore, SHapley Additive exPlanations (SHAP) analysis was used to examine the significance of prospective constituents. The results of the experiments substantiated these models. High coefficient of determination ( R 2 ) values (MEP: 0.950 and GEP: 0.913) indicated statistical significance, meaning that test results and anticipated outcomes were consistent with each other and with the MEP and GEP models, respectively. According to SHAP analysis, the amount of eggshell and glass powder (GP) had the most significant link with CS loss after acid deterioration, showing a positive and negative correlation, respectively. In order to optimize efficiency and cost-effectiveness, the created models possess the capability to theoretically assess the decline in CS of GP-modified mortar across various input parameter values. Graphical abstract

In this study, the effects of fly ash (FA) on the setting time, compressive strength, and hydration evolution of calcium sulphoaluminate (CSA) cement-based materials with high water content were investigated, targeting the design of a modified high-water material to delay excessively rapid setting time and enhance later-age strength. This was investigated using a combination of X-ray diffraction (XRD), Fourier transform infrared resonance (FTIR) spectroscopy, and Thermogravimetric Analysis (TGA). The results showed that the setting time of the high-water materials was delayed by increasing the FA content, with 15% being the optimal dosage for the setting time. A 5–10% content of FA is conducive to the development of later-age compressive strength and has a slight adverse effect on the early-age compressive strength of high-water materials. The microscopic test results show that FA mainly acts as a microaggregate in the early-age hydration process, whereas in the later-age hydration process, it promotes gypsum consumption and C 2 S hydration to form ettringite. The incorporation of FA effectively promotes ettringite formation in CSA cement-based materials with high water content. Therefore, the addition of FA can enhance the overall performance of high-water materials to a certain extent, and the long-term strength development of the material can satisfy engineering requirements. Graphical abstract

Self-compacting concrete (SCC) is well-known for its capacity to flow under its own weight, which eliminates the need for mechanical vibration and provides benefits such as less labor and faster construction time. Nevertheless, the increased cement content of SCC results in an increase in both costs and carbon emissions. These challenges are resolved in this research by utilizing waste marble and glass powder as cement substitutes. The main objective of this study is to create machine learning models that can predict the compressive strength (CS) of SCC using gene expression programming (GEP) and multi-expression programming (MEP) that produce mathematical equations to capture the correlations between variables. The models’ performance is assessed using statistical metrics, and hyperparameter optimization is conducted on an experimental dataset consisting of eight independent variables. The results indicate that the MEP model outperforms the GEP model, with an R 2 value of 0.94 compared to 0.90. Moreover, the sensitivity and SHapley Additive exPlanations analysis revealed that the most significant factor influencing CS is curing time, followed by slump flow and cement quantity. A sustainable approach to SCC design is presented in this study, which improves efficacy and minimizes the need for testing. Graphical abstract

To improve the utilization rate of municipal solid waste incineration (MSWI) ash and achieve resource recycling, this article conducted research on grinding MSWI ash into fine powder for use as a concrete admixture. Initially, the physical and chemical properties of the MSWI ash micro-powder were tested. Subsequently, different amounts of MSWI ash powder concrete were prepared. The macro and micro properties of the concrete were then tested. Finally, a life cycle assessment was utilized to evaluate and compare ordinary concrete with MSWI ash micro-powder concrete. The results indicate that the chemical composition of the MSWI ash micro-powder is similar to that of cement clinker. It exhibits potential hydraulicity and a slow hydration reaction, making it an active admixture suitable for concrete raw materials. With the increasing proportion of MSWI ash micro-powder, the rate of hydration reaction in concrete slows down, resulting in decreased mechanical properties. The microhardness value of the hardened cement paste in MSWI ash micro-powder concrete is lower than that of ordinary concrete. Moreover, the addition of MSWI ash micro-powder helps mitigate the environmental impact of concrete in terms of non-biological energy loss and CO 2 emissions.

The processing of γ-TiAl intermetallic compound (Ti–45Al–2Mn–2Nb) is essential for manufacturing aircraft engine components, known for their challenging machinability. This study delved into the machining performance of γ-TiAl intermetallic compound through ultrasonically assisted grinding experiments. Various grinding parameters, such as wheel rotation speed ( v s ), feed rate ( v w ), depth of grinding ( a p ), and ultrasonic amplitude ( A ), were investigated to understand their effects on grinding forces, temperatures, and surface quality. Gray relational analysis (GRA) and analysis of variance were used to analyze experimental data and ascertain the optimal machining parameters for ultrasonically assisted grinding of γ-TiAl intermetallic compound. Additionally, post-processing surface integrity, encompassing surface roughness, morphology, and residual stresses, was evaluated. The optimal grinding parameter combination was determined as F n = 3.22 N, F t = 1.08 N, and T = 174°C through GRA. Under the selected machining conditions, the depth of cut exerted the most significant influence on the grinding force and temperature, while the effect of wheel speed was the weakest. The surface roughness (Ra) of the workpiece increased with increasing feed rate and depth of the cut but decreased gradually with increasing wheel speed. Upon applying ultrasonic vibration, there was a notable decrease in surface roughness, ranging from 20.12 to 7.67%. However, the increase in the wheel speed, depth of cut, and feed rate inhibited the reduction of roughness due to ultrasonic vibration. Ultrasonic vibration effectively reduced the profile height of the workpiece surface, with a maximum reduction of 1.94 μm within the selected range. Nonetheless, as the wheel speed, depth of cut, and feed rate increased, the effectiveness of this reduction gradually diminished.

This study explores the possibilities of a new binding material, i.e. , marble cement (MC) made from recycled marble. It will assess how well it performs when mixed with ash from rice husks and fly ash. This research analyzes flexural strength of marble cement mortar (FR-MCM), a mortar that incorporates MC, fly ash, and rice husk ash. A set of machine learning models capable of predicting CS and FS (flexural and compressive strengths) were developed. Gene expression programming (GEP) and multi-expression programming (MEP) are crucial in creating these types of models. Statistics, Taylor’s diagrams, R 2 values, and comparisons of experimental and theoretical results were used to evaluate the models. Stress testing also showed how different input features affected the model’s outputs. The accuracy of all GEP models was shown to fall within the acceptable range ( R 2 = 0.952 for CS and R 2 = 0.920 for FS), and all MEP prediction models were determined to be exceptionally accurate ( R 2 = 0.970 for CS and R 2 = 0.935 for FS). The statistical testing for error validation also verified that MEP models were more accurate than GEP models. According to sensitivity analysis, curing age and rice husk ash exerted the most significant influence on the prediction of CS and FS, followed by fly ash and MC. Graphical Abstract

Steam curing prefabrication is a feasible way to promote the application of recycled aggregate in the background of building industrialization. The combined use of slag and fly ash contributes to the comprehensive improvement of both the early and later-stage performance of recycled aggregate concrete (RAC). However, the steam curing regime for RAC composed of slag and fly ash remains unclear, including appropriate curing temperatures and time. In this study, the influences of curing temperatures (20, 40, 60, and 80°C), steam curing time (6, 9, and 12 h) and mineral admixtures (slag powder and fly ash) on the demoulding strength and strength development of RAC were investigated. Based on the Arrhenius formula, the hydration reaction rate was characterized by the development of compressive strength, the apparent activation energy related to the steam curing time was calculated, and the energy-based compressive strength model was proposed to realize the early strength prediction of the steam-cured RAC.

By collecting engineered cementitious composite (ECC) uniaxial tensile experimental research data, aiming at the multiple cracking characteristics of the strain hardening stage of the ECC stress–strain curve, a theoretical model describing the constitutive relationship of the ECC uniaxial tensile stress–strain – the multiple cracking sawtooth model – is proposed. Several model parameters were obtained with the fitting analysis of many ECC uniaxial tensile stress–strain curves. The application conditions and influencing factors of the three-order multi-crack “sawtooth” model of polyvinyl alcohol (PVA)-ECC and polyethylene (PE)-ECC and the four-order multi-crack “sawtooth” model of PVA-ECC are studied. The result shows that the higher the fiber reinforcement index, the better the tensile properties of ECC. The fiber reinforcement index is linearly correlated with the initial crack stress and ultimate tensile stress of PVA-ECC and with the ultimate tensile stress and ultimate tensile strain of PE-ECC. The characteristic points of PVA-ECC in the multi-crack cracking stage are as follows: the greater the initial cracking strain, the smaller the ultimate tensile strain, showing an exponential correlation; The greater the initial cracking stress is, the greater the ultimate tensile stress is, and the two are linearly correlated.

Using rice husk ash (RHA) as a cement substitute in concrete production has potential benefits, including cement consumption and mitigating environmental effects. The feasibility of RHA on concrete strength was investigated in this research by predicting the split tensile strength (SPT) and flexural strength (FS) of RHA concrete (RHAC). The study used machine learning (ML) methods such as ensemble stacking and gene expression programming (GEP). The stacking model was improved using base learner configurations ML models, such as, random forest (RF), support vector regression, and gradient boosting regression. The proposed models were validated by statistical tests and external validation criteria. Moreover, the effect of input parameters was investigated using Shapley adaptive exPlanations (SHAP) for RF and parametric analysis for GEP-based models. The analysis revealed that the stacking ensemble integrates base learner predictions and demonstrated superior performance, with R values greater than 0.98 and 0.96. Mean absolute error and root mean square error values for both SPT and FS were 0.23, 0.3, 0.5, and 0.7 MPA, respectively. The SHAP analysis demonstrated water, cement, superplasticizer, and age as influential parameters for the RHAC strength. Furthermore, the SPT and FS of RHAC can be predicted with an acceptable error using the GEP expressions in the standard design procedure. Graphical abstract

Plastic waste (PW) poses a significant threat as a hazardous material, while the production of cement raises environmental concerns. It is imperative to urgently address and reduce both PW and cement usage in concrete products. Recently, several experimental studies have been performed to incorporate PW into paver blocks (PBs) as a substitute for cement. However, the experimental testing is not enough to optimize the use of waste plastic in pavers due to resource and time limitations. This study proposes an innovative approach, integrating experimental testing with machine learning to optimize PW ratios in PBs efficiently. Initially, experimental investigations are performed to examine the compressive strength (CS) of plastic sand paver blocks (PSPBs). Varied mix proportions of plastic and sand with different sizes of sand are employed. Moreover, to enhance the CS and meet the minimum requirements of ASTM C902-15 for light traffic, basalt fibers, a sustainable industrial material, are also utilized in the manufacturing process of environmentally friendly PSPB. The highest CS of 17.26 MPa is achieved by using the finest-size sand particles with a plastic-to-sand ratio of 30:70. Additionally, the inclusion of 0.5% basalt fiber, measuring 4 mm in length, yields further enhancement in outcome by significantly improving CS by 25.4% (21.65 MPa). Following that, an extensive experimental record is established, and multi-expression programming (MEP) is used to forecast the CS of PSPB. The model’s projected results are confirmed by using various statistical procedures and external validation methods. Furthermore, comprehensive parametric and sensitivity studies are conducted to assess the effectiveness of the MEP-based proposed models. The sensitivity analysis demonstrates that the size of the sand particles and the fiber content are the primary factors contributing to more than 50% of the CS in PSPB. The parametric analysis confirmed the model’s accuracy by demonstrating a comparable pattern to the experimental results. Furthermore, the results indicate that the proposed MEP-based formulation exhibits high precision with an R 2 of 0.89 and possesses a strong ability to predict. The study also provides a graphical user interface to increase the significance of ML in the practical application of handling waste management. The main aim of this research is to enhance the reuse of PW to promote sustainability and economic benefits, particularly in producing green environments with integration of machine learning and experimental investigations. Graphical abstract

This work inspects 3D magnetohydrodynamic hybrid nanofluid flow on a permeable elongating surface. The emphasis of this paper is on the study of hybrid nanofluid flow within a rotating frame, taking into account the simultaneous impact of both thermal and velocity slip boundary conditions. The chosen base fluid is water, and the hybrid nanofluid comprises two nanoparticles Cu \text{Cu} and Al 2 O 3 {\text{Al}}_{2}{\text{O}}_{3} . The effect of the magnetic and porosity parameters is taken into account in the momentum equation. The thermal radiation, Joule heating, and heat source are considered in the energy equation. Using a similarity system, we transform the PDEs of the proposed model into ODEs, which are then solved numerically by the bvp4c technique. The magnetic field shows a dual nature on primary and secondary velocities. Enrich magnetic field decreases the primary velocity and enhances the secondary velocity. The rotation parameter has an inverse relation with both velocities. The temperature profile amplified with the escalation in heat source, magnetic field, rotation factor, and Eckert numbers. The skin friction is boosted with magnetic parameters while the Nusselt number drops.

One of the basic fluid mechanics problems of fluid flows over a revolving disk has both theoretical and real-world applications. The flow over a rotating disk has been the subject of numerous theoretical studies because it has many real-world applications in areas like rotating machinery, medical equipment, electronic devices, and computer storage. It is also crucial for engineering processes. Therefore, this article deals with a time-independent water-based hybrid nanofluid flow containing copper oxide and silver nanoparticles past a spinning disk. The Newtonian flow is taken into consideration in this analysis. The influence of magnetic field, thermophoresis, nonlinear thermal radiation, Brownian motion, and activation energy has been considered. The present analysis is modeled in a partial differential equation form and is then converted to ordinary differential equations using appropriate variables. A numerical solution using the bvp4c technique is accomplished using MATLAB software. The current results are matched with the previous literature and established a close relationship with previous studies. The purpose of this investigation is to numerically investigate the time-independent hybrid nanofluid flow comprising copper oxide and silver nanoparticles over a rotating disk surface. The results show that the increased magnetic parameters increase the friction force at the surface, which decreases the radial and azimuthal velocity distribution. At the sheet surface, the radial velocity of the hybrid nanofluid shows dominant performance compared to the nanofluid. On the other hand, the magnetic factor has dominant behavior on the azimuthal velocity component of the nanofluid flow compared to the hybrid nanofluid flow. The higher volume fraction and magnetic factor enhance the skin friction at the disk surface. Furthermore, greater surface drag is found for the hybrid nanofluid flow. The higher solid volume fraction, temperature ratio, and Biot number enhance the rate of heat transmission. Also, a higher rate of heat transmission is observed for the hybrid nanofluid flow.

Currently, there is a lack of research comparing the efficacy of machine learning and response surface methods in predicting flexural strength of Concrete with Eggshell and Glass Powders. This research aims to predict and simulate the flexural strengths of concrete that replaces cement and fine aggregate with waste materials such as eggshell powder (ESP) and waste glass powder (WGP). The response surface methodology (RSM) and artificial neural network (ANN) techniques are used. A dataset comprising previously published research was used to assess predictive and generalization abilities of the ANN and RSM. A total of 225 research article samples were collected and split into three subsets for model development: 70% for training (157 samples), 15% for validation (34 samples), and 15% for testing (34 samples). ANN used seven independent variables to model and improve the model, whereas RSM used three variables (cement, WGP, and ESP) to improve the model. The k -fold cross-validation validated the generalizability of the model, and the statistical metrics demonstrated favorable outcomes. Both ANN and RSM techniques are effective instruments for predicting flexural strength, according to the statistical results, which include the mean squared error, determination coefficient ( R 2 ), and adjusted coefficient ( R 2 adj). RSM was able to achieve an R 2 of 0.7532 for flexural strength, whereas the accuracy of the results for ANN was 0.956 for flexural strength. Moreover, the correlation between the ANN and RSM models and the experimental data was high. However, the ANN model exhibited superior accuracy.

The degradation of concrete structures is significantly influenced by water penetration since water serves as the primary vehicle for the movement of harmful compounds. The process of capillary water absorption is widely recognized as a crucial indicator of durability for unsaturated concrete, as it allows dangerous substances to enter the composite material. The water absorption capacity of concrete is intricately linked to its pore structure, as concrete is inherently porous. The main goal of this work is to create an innovative predictive tool that assesses the porosity of concrete by analyzing its components using a machine-learning (ML) framework. Seven distinct batch design variables were included in the generated database: fly ash, superplasticizer, water-to-binder ratio, curing time, ground granulated blast furnace slag, binder, and coarse-to-fine aggregate ratio. Four distant ML algorithms, including AdaBoost, linear regression (LR), decision tree (DT), and support vector machine (SVM), are utilized to infer the generalization capabilities of ML algorithms to estimate concrete porosity accurately. The RReliefF algorithm was implemented to calculate the significant features influencing porosity. This study concludes that in comparison to the alternative techniques, the AdaBoost method demonstrated superior performance with an R 2 score of 0.914, followed by SVM (0.870), DT (0.838), and LR (0.763). The results of the evaluation of RReliefF indicated that the binder possesses a remarkable influence on the porosity of concrete.

This study focuses on the comprehensive exploration of Swat soapstone, employing a range of analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and X-ray fluorescence (XRF) spectroscopy. XRD was used to identify the phase and lattice parameters of the soapstone. SEM further scrutinizes the dispersed soapstone particles, revealing different structural characteristics such as a slightly elongated, cubic-like structure, a straight rod-like formation, and a rough, textured surface. EDX spectroscopy was utilized for studying the elemental composition of the soapstone. The analysis identifies talc as the primary mineral in Swat soapstone, with iron, an element, also contributing notably to its composition. This underscores the complexity of Swat soapstone’s internal structure. XRF analysis further contributes to the elemental characterization, revealing a dominant composition of silicon (Si) at 48.567 wt% and a notable contribution from iron (Fe) at 16.108 wt%. FTIR analysis confirmed the absorption of infrared radiation at the non-bridging oxygen (Si–O–) within the silicate network and the Si–O–Si bending vibration. This work investigates the chemical and morphological details of the Swat soapstone.

In order to solve the problems of depleting petroleum asphalt resources and deteriorating pollution of marine products, a systematic study was carried out on the application prospect of waste crab shell (WS) powder as asphalt modifier. In this study, the physical properties of WS powder modified asphalt (WSA) were tested by blending different contents of WS powder into matrix asphalt; the high and low temperature rheological properties of WS powder modified asphalt were characterized by using Dynamic shear rheometer, Bending beam rheometer, and Multiple stress creep recovery test. In addition, the microscopic chemical properties and modification mechanism were analyzed by Differential scanning calorimetry, Fourier transform infrared spectroscopy, Atomic force microscopy, and Scanning electron microscope. It was shown that the WS powder enhanced the viscoelastic properties, temperature sensitivity properties, and permanent deformation resistance of asphalt. In addition, there was no obvious chemical reaction between the WS powder and the matrix asphalt, and no new chemical substances were generated; at the microscopic level, the WS powder and the matrix asphalt had good compatibility. In conclusion, the use of WS powder as a bio-based asphalt modifier to improve the resources and environmental issues have certain prospects.

To achieve the improving effect of polymer material on the sustainability of asphalt pavement materials, the PW modifier was selected as anti-aging modifier of asphalt. The microscopic morphology and structural characteristics of polymer modifier were characterized by using focused ion beam electron microscopy and energy-dispersive spectrometer. The functional group composition of the PW modifier was analyzed by Fourier transform infrared spectroscopy. The PW-modified asphalt was prepared for ultraviolet (UV) aging resistance evaluation. The microscopic morphology and surface roughness evolution of polymer-modified asphalt were investigated during the whole period of UV aging. Under the condition of UV aging, the functional group composition of polymer-modified asphalt was studied. The results showed that the microscopic morphology of the PW polymer modifier was mainly crystal structure, mainly composed of C and O elements. The PW polymer modifier could improve the aging resistance of asphalt binder effectively and alleviate the generation of asphalt microcracks in the process of UV aging. The addition of PW polymer modifier could inhibit the formation and accumulation of typical functional group inside asphalt binder during the UV aging period, which could achieve the effective control of asphalt UV aging behavior.

Size uniformity is a key challenge in the preparation of hydrothermal carbon spheres and a prerequisite for size effect research and many applications of carbon spheres. To solve the scientific problem of low uniformity due to the slow carbonization in traditional preparation of glucose carbon spheres, we propose to add acid/base catalysts to accelerate nucleation, shorten the nucleation time, and improve the size uniformity of carbon spheres. The carbon spheres prepared under base conditions versus acid conditions have higher uniformity and smaller particle size (particle size = 503 nm). This result is due to the faster accumulation of aromatic clusters, shorter nucleation time, and larger number of carbon spheres in alkaline systems. The NaOH-HCSs-based solid acid catalyst as-prepared exhibits excellent catalytic activity, and the esterification rates of levulinic acid and n -butanol maximize to 96.36%.

Activated alkali materials (AAMs) are progressively utilized as an alternative to Portland cement concrete owing to their widespread application and reduced environmental impact. This research employed multi-expression programming (MEP) and gene expression programming (GEP) to create predictive models for the compressive strength (CS) of AAMs based on a dataset of 381 entries with eight distinct variables. To further assess the significance of the factors influencing the CS of AAMs, sensitivity analysis was employed. In comparison to GEP, MEP was better at predicting AAM’s CS. The R 2 score of the GEP model was 0.953, which is lower than the MEP model’s 0.970 level. This was further backed up by the results of the statistical study and Taylor’s diagram. The results of the sensitivity analysis showed that specific surface area, aggregate volumetric ratio, and silicate modulus were the three most important parameters influencing the models’ outcomes. In comparison to models built in Python, the produced models yield novel empirical equations for AAM strength characteristic prediction. Researchers and professionals in the field could use these equations to find the best proportions for mix designs, cutting down on the need for repeated laboratory tests.

The aim of this study was to develop yeast-based microcapsules (YBMCs) containing vegetable oil blends with n3/n6 fatty acids in a ratio of 5:1. The oil blends, as well as YBMCs with these oils, were analyzed in nitrogen and oxygen. The shape and course of the TG and DTG curves were observed for yeast cells with all types of oil blends. No differences were observed in shape because of the microencapsulation curves with all oil blends between YMBCs prepared using native and autolyzed yeast. The results show that the yeast cells could be used as efficient microcarriers for the encapsulation of cold-pressed oils in order to provide thermal stable ingredients for the food industry.

Considering the temperature sensitivity and two-phase incompatibility of the fiber matrix interface, carbon fiber-reinforced thermoplastic composites suffer from weak interfacial bonding strength. To investigate the delamination damage and shear failure mechanism of T700/PEEK composites at varying temperatures, interfacial shear strength (IFSS) and interlaminar shear strength (ILSS) were performed by employing micro debonding experiments and three-point bending. The results indicated that at temperatures below the glass transition, the IFSS of T700/PEEK composites was positively correlated with temperature, and the average strength recorded was 52 ± 6 MPa. When the glass transition temperature was exceeded, the bonding state between polyether ether ketone material and fiber surface became tighter, resulting in a slight increase in IFSS, reaching 60 ± 4 MPa. Further, the ILSS of T700/PEEK composites was tested, and the results indicated a negative correlation between ILSS and temperature, with a maximum ILSS of 40 ± 2 MPa observed at 23°C, and a minimum of 11 ± 1 MPa recorded at 230°C. The decline in bending strength observed with increasing temperature was attributed to the separation of the fiber and matrix interface at high temperatures, which reduced the mechanical properties of T700/PEEK composites. By conducting temperature related mechanical performance tests on T700/PEEK composite materials, the obtained test results will help researchers expand the application scenarios of this material, deepen the relationship between the temperature and its performance, and thus more quickly explore the mechanism of temperature action. Graphical abstract

The structure tensor (ST), also named a second-moment matrix, is a popular tool in image processing. Usually, its purpose is to evaluate orientation and to conduct local structural analysis. We present an efficient algorithm for computing eigenvalues and linking eigenvectors of the ST derived from a material structure. The performance and efficiency of our approach are demonstrated through several numerical simulations. The proposed approach is evaluated qualitatively and quantitatively using different two-dimensional/three-dimensional wood image types. This article reviews the properties of the first- and second-order STs, their properties, and their application to illustrate their usefulness in analyzing the wood data. Our results demonstrate that the suggested approach achieves a high-quality orientation trajectory from high-resolution micro-computed tomography ( μ {\rm{\mu }} CT)-imaging. These orientations lead to establishing a description of fiber orientation states in thermo-mechanical models for fiber-reinforced composite materials. We conclude with an overview of open research and problem directions.

Three-dimensional (3D) printing technology can be used to fabricate layer-by-layer regular porous polydimethylsiloxane (PDMS) structures with excellent superhydrophobic ability and mechanical stability. However, for engineering applications, the design must consider the structure and superhydrophobicity of the resulting material. In this study, we propose an approach to regulate the mechanical properties of PDMS by adjusting the layered pattern, such as by changing filament orientation with 30°, 45°, and 90° angle steps and using staggered structures with a half-shifted spacing. A finite element analysis was conducted to investigate how the layered pattern influenced the tensile and compressive properties. The results reveal that a layered, staggered design can modulate the compressive properties of the porous PDMS, particularly the ratio between the compressive moduli of the sample without and with staggered structures could reach as high as 686% when the layering angle is 0°/90°. The tensile properties are better regulated by the filament angle rather than by the staggered design and improve as the raster angle of the filaments increases. This occurs when the upper and lower filaments tend toward orthogonality. Thus, the required layered pattern can be selected, enabling the integrated design of mechanical properties and function in 3D-printed porous PDMS. Graphical abstract

This study examines the impact of using seashell powder, shells mixed with nano-silica, and basic oxygen furnace slag as sand substitutes in addition to the internal curing regime. This study focuses on important factors related to material sustainability and the efficient use of resources. The comprehensive evaluation of mechanical properties, including compressive and tensile strength at different stages, provides a significant understanding of the performance improvements achieved with these innovative additives. Durability tests, which evaluate the absorption, water permeability, salt penetration, and sulfate resistance, advance our understanding of how these materials enhance the long-term durability of ultra-high-performance concrete (UHPC) under extreme environmental conditions. In addition, examining UHPC samples at high temperatures (350 and 700°C) and applying scanning electron microscopy. The improved mechanical strength and toughness achieved using seashells and nano-silica demonstrated the potential of these additives to create UHPC that is more sustainable and environmentally friendly. The results indicate that the addition of seashell powder slightly reduced the compressive strength. However, replacing cement with a blend of seashells and nano-silica led to an improvement ranging from 5 to 6% in compressive strength across various replacement ratios at 7, 28, and 90 days. The optimum strength is obtained at a 5% replacement ratio. Tensile strength also increased from 1.6 to 1.8 MPa when seashells were pre-mixed with nano-silica. The incorporation of nano-silica significantly enhanced the thermal stability of the seashells, resulting in a better residual strength of 84–93% at 350°C and ranged from 68 to 82% at 700°C. Furthermore, the combination of seashells and seashell powder with nano-silica notably improved durability by reducing the water permeability, sorptivity, and chloride penetration depth. The residual strength of UHPC showed greater improvement after exposure to a sulfate environment when the seashells were combined with nano-silica than when seashells alone were used and achieved 81 MPa compared to 69.1 MPa for the control mix and 74 MPa for seashells only. Overall, the inclusion of seashells pre-mixed with nano-silica in UHPC enhanced the microstructure at both normal and elevated temperatures.

The relationship between fly ash (FA) and silica fume (SF)-modified magnesium phosphate cement (MPC) at varying temperatures remains unclear. In this study, the mechanical properties and damage characteristics of FA- and SF-modified MPC at 20–1,000°C were analysed through uniaxial compression tests. The results indicate that the compressive strength of MPC diminishes at varying temperatures, while FA and SF can enhance the compressive strength of MPC following exposure to high temperatures. In addition, with an increase in the temperature, the peak strain of MPC increased, and the deformation modulus first decreased and then increased. At 1,000°C, the deformation modulus of MPC was 5.09–10.92 GPa. The proposed damage constitutive model can predict the mechanical parameters of FA- and SF-modified MPC at different temperatures. The total damage variable reflects an “S-shaped” change trend under the action of axial compression loads. MPC exhibited irreversible initial temperature damage after being treated at different temperatures. More specifically, the temperature damage variable first increased and then decreased by increasing the temperature. At 600°C, the temperature damage variable exceeds 30% of the total damage variable associated with the peak strain, and at 1,000°C, it surpasses 10%.

This research integrated glass powder (GP), marble powder (MP), and silica fume (SF) into rubberized mortar to evaluate their effectiveness in enhancing compressive strength ( f c ′ {f}_{\text{c}}^{^{\prime} } ). Rubberized mortar cubes were produced by replacing fine aggregates with shredded rubber in varying proportions. The decrease in rubberized mortar’s f c ′ {f}_{\text{c}}^{^{\prime} } was controlled by substituting cement with GP, MP, and SF. Although many literature studies have evaluated the suitability of industrial waste, such as MP, SF, and GP, as construction material, no studies have yet included the combined effect of these wastes on the f c ′ {f}_{\text{c}}^{^{\prime} } of rubberized mortar. This study aims to provide complete insight into the combined effect of industrial waste on the f c ′ {f}_{\text{c}}^{^{\prime} } of rubberized mortar. By substituting cement, GP, MP, and SF were added to rubberized mortar in different proportions from 5 to 25%. Furthermore, artificial intelligence prediction models were developed using experimental data to assess the f c ′ {f}_{\text{c}}^{^{\prime} } of rubberized mortar. The study determined that the optimal substitution levels for GP, MP, and SF in rubberized mortar were 15, 10, and 15%, respectively. Similarly, partial dependence plot analysis suggests that SF, MP, and GP have a comparable effect on the f c ′ {f}_{\text{c}}^{^{\prime} } of rubberized mortar. The machine learning models demonstrated a significant resemblance to test results. Two individual techniques, support vector machine and random forest, generate R 2 values of 0.943 and 0.983, respectively.

Triply periodic minimal surface (TPMS) metamaterials possess exceptional properties not commonly found in natural materials. TPMS metamaterials are used in lightweight structures and impact energy absorption structures due to their surface geometry and mechanical properties. The quasi-static mechanic properties of resin-based homogeneous and gradient TPMS structures manufactured by stereolithography are investigated in this study. The results of both experimental and numerical simulations reveal that the gradient TPMS structures have superior energy absorption abilities compared to the homogeneous TPMS structures. Furthermore, the benefits of gradient TPMS structures can be further enhanced by changing the gradient variation interval of the relative density and cell thickness of TPMS. If the slope and intercept of the C value function of the TPMS structures remain constant, selecting a design where the gradient direction of the cell aligns with the direction of the load on the material can enhance the energy absorption capability of the TPMS structures.

Bioprinting has a critical role in tissue engineering, allowing the creation of sophisticated cellular scaffolds with high resolution, shape fidelity, and cell viability. Achieving these parameters remains a challenge, necessitating bioinks that are biocompatible, printable, and biodegradable. This review highlights the potential of marine-derived polymers and crosslinking techniques including mammalian collagen and gelatin along with their marine equivalents. While denaturation temperatures vary based on origin, warm-water fish collagen and gelatin emerge as promising solutions. Building on the applications of mammalian collagen and gelatin, this study investigates their marine counterparts. Diverse research groups present different perspectives on printability and cell survival. Despite advances, current scaffolds are limited in size and layers, making applications such as extensive skin burn treatment or tissue regeneration difficult. The authors argue for the development of bioprinting, which includes spherical and adaptive printing. In adaptive printing, layers differentiate and propagate sequentially to overcome the challenges of multilayer printing and provide optimal conditions for the growth of deeply embedded cells. Moving the boundaries of bioprinting, future prospects include transformative applications in regenerative medicine.

4D printing is recognised for its numerous potential applications due to its reaction towards stimulus factors. However, limited research has focused on what, why, and how this stimulus-response works. This study reveals the mechanism used to stimulate 4D printing reactions. Complex printing via design structure and mechanical control on fibre orientations are promising techniques compared with chemical modifications, which are difficult to control, particularly for commercialisation.

4D printing, the fabrication of dynamic 3D objects, has emerged as a frontier in additive manufacturing, benefiting from rapid advancements in 3D printing technologies and the development of new stimuli-responsive materials. Among the diverse materials explored for 4D printing, the hydrogel, renowned for its exceptional flexibility, biocompatibility, and tunable mechanical properties, is a class of soft materials well-suited for 4D printing. In addition to selecting and developing appropriate stimuli-responsive materials, it is important to devise suitable printing strategies to enable the fabrication of hydrogel-based structures that can perform complex shape-changing under external stimuli in various applications, such as soft robotics and biomedical areas. In view of this, various printing strategies, including structural design, printing scheme, and stimuli control are systematically summarized. This review aims to provide an up-to-date evolution of 4D-printed hydrogels and insights into the utilization of these printing strategies and printing techniques, such as direct ink writing, stereolithography, and two-photon polymerization, in the 4D printing of hydrogel structures for specific functions and applications.

3D printing is one of the plastic recycling processes that deliver a mechanically sustainable product and may be used for 4D printing applications, such as self-assembly, sensors, actuators, and other engineering applications. The success and implementation of 4D printing are dependent on the tendency of the shape memory with the action of external stimuli, such as heat, force, fields, light, and pH. Acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) are the most common materials for fused filament fabrication-based 3D printing processes. However, the low-shaped memory tendency on heating and weaker and less rigidity of ABS limit the application domains. PLA is an excellent responsive behavior when the action of heat has high stiffness. The incorporation of PLA into ABS is one of the solutions to tune the shape memory effect for better applicability in the 4D printing domain. In this study, the primary recycled PLA was incorporated into the primary recycled ABS matrix from 5 to 40% (weight%), and composites were made by extrusion in the form of cylindrical filaments for 4D printing. The tensile and shape memory properties of the recycled ABS–PLA composites were investigated to select the best combination. The results of the study were supported by fracture analysis by shape memory analysis, scanning electron microscopy, and optical microscopy. This study revealed that the prepared ABS–PLA-based composites have the potential to be applied in self-assembly applications.

Popular and eco-friendly alkali-activated materials (AAMs) replace Portland cement concrete. Due to the considerable compositional variability of AAMs and the inability of established materials science methods to understand composition–performance relationships, accurate property forecasts have proved impossible. This study set out to develop AAM compressive strength (CS) evaluation machine learning (ML) models using techniques including extreme gradient boosting (XGB), bagging regressor (BR), and multi-layer perceptron neural network (MLPNN). Ten input variables were used with a large dataset of 676 points. Statistical and K-fold studies were also used to evaluate the developed models’ correctness. XGB predicted the CS of AAM the best, followed by BR and MLPNN. The MLPNN and BR models had R 2 values of 0.80 and 0.90, respectively, whereas the XGB model had 0.94. Results from statistical analyses and k-fold cross-validation of the used ML models further attest to their validity. The built models can potentially compute the CS of AAMs for a variety of input parameter values, reducing the requirement for costly and time-consuming laboratory testing. Researchers and businesses may find this study useful in determining the necessary quantities of AAMs’ raw components.

The glulam-cross laminated timber (CLT) composite floor is a type of prefabricated composite floor that integrates glulam beams and CLT slab into a unified structure using shear connectors. To investigate the bending performance of the glulam-CLT composite floor, the bending test was conducted on a full-scale composite floor under static load. The study comprehensively analyzed the failure mechanism, load–deflection behavior, interface slip and strain distribution of the glulam-CLT composite floor. The test results of the composite floor indicated that the failure mode was tensile fracture of the wood beam at the bottom. As the load increased, the deflection deformation of the mid-span beam exceeded that of the edge beam. When the load reached its ultimate limit, the deflection deformation of the mid-span beam increased by 14.4% compared to the edge beam. In the early loading phase, the strain distribution of the composite section satisfied the assumption of a plane section. However, the strain distribution deviated from this assumption with the increased load due to the relative slips between the glulam beam and CLT flange. To calculate the bending performance of the composite floor, the M-shaped section of the glulam-CLT composite floor was simplified as T-section composite beams. The linear-elastic method for determining the flexural rigidity and ultimate bearing capacity of the glulam-CLT composite floors was proved to be accurate and reliable. The findings provided valuable insights into the bending behavior of the CLT flange under load and emphasized the non-uniform stress distribution caused by shear lag effects.

Using supplementary cementitious materials in concrete production makes it eco-friendly by decreasing cement usage and the corresponding CO 2 emissions. One key measure of concrete’s durability performance is its porosity. An empirical prediction of the porosity of high-performance concrete with added cementitious elements is the goal of this work, which employs machine learning approaches. Binder, water/cement ratio, slag, aggregate content, superplasticizer (SP), fly ash, and curing conditions were considered as inputs in the database. The aim of this study is to create ML models that could evaluate concrete porosity. Gene expression programming (GEP) and multi-expression programming (MEP) were used to develop these models. Statistical tests, Taylor’s diagram, R 2 values, and the difference between experimental and predicted readings were the metrics used to evaluate the models. With R 2 = 0.971, mean absolute error (MAE) = 0.348%, root mean square error (RMSE) = 0.460%, and Nash–Sutcliffe efficiency (NSE) = 0.971, the MEP provided a slightly better-fitted model and improved prediction performance when contrasted with the GEP, which had R 2 = 0.925, MAE = 0.591%, RMSE = 0.745%, and NSE = 0.923. Binder, water/binder ratio, curing conditions, and aggregate content had a direct (positive) relationship with the porosity of concrete, while SP, fly ash, and slag had an indirect (negative) association, according to the SHapley Additive exPlanations study.

The mechanical strength of geopolymer concrete incorporating corncob ash and slag (SCA-GPC) was estimated by means of three distinct AI methods: a support vector machine (SVM), two ensemble methods called bagging regressor (BR), and random forest regressor (RFR). The developed models were validated using statistical tests, absolute error assessment, and the coefficient of determination ( R 2 ). The importance of various modeling factors was determined by means of interaction diagrams. When estimating the flexural strength and compressive strength of SCA-GPC, R 2 values of over 0.85 were measured between the actual and predicted findings using both individual and ensemble AI models. Statistical testing and k -fold analysis for error evaluation revealed that the RFR model outperformed the SVM and BR models in terms of accuracy. As demonstrated by the interaction graphs, the mechanical characteristics of SCA-GPC were found to be extremely responsive to the mix proportions of ground granulated blast furnace slag, fine aggregate, and corncob ash. This was the case for all three components. This study demonstrated that highly precise estimations of mechanical properties for SCA-GPC can be made using ensemble AI techniques. Improvements in geopolymer concrete performance can be achieved by the implementation of such practices.

Concrete is the second-most used material globally and significantly impacts the environment by emitting a large amount of carbon dioxide (CO 2 ). This scientometric review investigates the sustainable use of waste glass (WG) in concrete. Our study examines the impact of waste glass powder (WGP) on the mechanical and fresh characteristics of concrete and its environmental implications, enhanced by a machine learning prediction model. We observed a progressive increase in research activity on WGP-based concrete since 2000, indicating the growing interest in this area. The primary focus areas are engineering and material science, reflecting the application potential, structural performance, and material properties of WGP-based concrete. Our discussions highlight the significant benefits of WGP in concrete, including its potential to reduce landfill usage, environmental pollution, and enhance properties such as strength, sulfate resistance, alkali–silica reaction resistance, and freeze–thaw resistance. The review also explores the microstructure of glass powder (GP)-based concrete, illuminating the complex interactions between glass particles and the concrete matrix, which influence the material’s overall performance. Environmental impact assessments underscore the necessity for sustainable construction practices and waste reduction. Utilizing machine learning prediction models helps optimize the composition of GP-based concrete, thus enhancing material performance and durability. This review provides a comprehensive analysis of using WG in concrete, contributing to the field’s understanding and informing future research and innovations to optimize WG use in concrete applications.

This research examines the efficiency of ultra-high-performance concrete (UHPC) when utilizing geranium plant (GP) ash, which is subjected to different curing temperatures ranging from 300 to 900°C for 3 h of burning time. The GP ash is used as a replacement for cement in varying amounts (10, 20, 30, 40, and 50 wt%). Crumb rubber powder is utilized as a substitute for fine aggregate. Polypropylene fibers have been used to improve concrete performance. The performance of UHPC is evaluated by assessing its mechanical qualities, such as flexural strength, splitting tensile strength, and compressive strength. The sorptivity test is also evaluated as a component of it. Scanning electron microscopy is used to analyze UHPC after exposure to temperatures as high as 900°C. The findings demonstrated a notable enhancement in the mechanical characteristics of all mixtures. The most favorable mixtures were achieved with proportions of 50, 40, 40, and 20% for mixtures including GP waste incinerated at temperatures ranging from 300 to 900°C. Furthermore, the optimal outcome is achieved when 40% substitution is performed at a temperature of 700°C, resulting in notable enhancements of 14% in compressive strength, 30% in flexural strength, and 17% splitting tensile strength, respectively. At a high temperature of 700°C, the decrease in strength increased to approximately 37–40% as a result of the initial removal of carbon dioxide from calcite at temperatures ranging from 600 to 900°C and reached 56% at 900°C. Great resistance to sorptivity, as well as a dense and compact microstructure with a high content of calcium and silicon, was obtained.

Geopolymers have emerged as promising alternatives to traditional cement-based composites, offering enhanced sustainability and opportunities for recycling industrial waste. The incorporation of waste materials into the binding matrix of geopolymer concrete not only promotes environmental benefits but also significantly improves the overall performance, including mechanical strength, durability, and microstructural integrity of the matrix. This study explores the impact of incorporating varying dosages of nano-basic oxygen furnace slag (NBOFS) and nano-banded iron formation (NBIF) on the properties of high-performance geopolymer concrete (HPGC) that utilizes waste glass as 50% fine aggregate. The research focuses on evaluating both the fresh and mechanical properties, including compressive strength, splitting tensile strength, modulus of elasticity, and flexural strength. Additionally, this study investigated the transport properties of concrete under aggressive environments, such as resistance to chloride penetration, sulfate attack, and sorptivity. The microstructure was examined using scanning electron microscopy. The results demonstrated that the addition of 3% NBOFS and 2.5% NBIF significantly improved the fresh, mechanical, and transport properties of HPGC. These nanomaterials also enhance the splitting tensile strength, flexural strength, and elastic modulus under highly aggressive environmental conditions. The contribution of these nanomaterials to the strength and durability of concrete is particularly relevant in the construction of both substructures and superstructures. Additionally, geopolymer concrete significantly reduces CO 2 emissions by eliminating the requirement for ordinary Portland cement and promoting the recycling of waste products, contributing to more environmentally friendly construction practices.

Durability degradation in reinforced concrete (RC) constructions is commonly attributed to the steel reinforcement corrosion caused by chloride. The utilization of supplemental cementitious resources, such as waste materials from industrial and agricultural sectors, typically improves the impermeability and strengthens concrete resistance to corrosion, sulfate, and acid attacks. Therefore, the prevention of steel reinforcement corrosion is greatly important in resolving challenges related to the durability and stability of RC structures, particularly when utilizing agriculture waste materials. This approach also serves as a solution for waste disposal. The aim of this study is to investigate the corrosion-resistant characteristics of high-strength concrete that contains ultrafine palm oil fuel ash (U-POFA) as a partial replacement for cement. Four high-strength green concrete (HSGC) mixes were investigated in this study with a partial replacement of ordinary Portland cement (OPC) by U-POFA at 0, 20, 40, and 60% by mass. The aim of this study is to analyze the workability, strength activity index (SAI), compressive strength, rapid chloride permeability, linear polarization resistance (LPR) by different measurement methods, and four-probe resistivity measurement by electrical resistivity measurement method of over a curing period of 7, 28, 60, and 90 days. The use of U-POFA in the different mixes results in improved workability, SAI, compression strength, and chloride penetration resistance compared with the zero-POFA mix. It is clear from the study results that adding U-POFA as a partial replacement for OPC improved the corrosion resistance of HSGC mixtures. Thus, the incorporation of U-POFA 60% succeeded in reducing the chloride ion penetration by 80% and the LPR by 93% at the test age of 90 days, compared to the reference mixture. Graphical abstract

This study examines the effect of adding different dosages of nontitanium (NT) and nano-silica (NS) ranging from 0.5 to 4% by weight of binder materials on ultra-high-performance geopolymer concrete (UHPGC). The material’s feasibility was evaluated using slump flow measurements. A detailed analysis of its compressive strength (CS), transport properties, and sulfate attack was conducted. The addition of 2.5% NS and 4% NT improved the CS and transport properties of UHPGC compositions, creating a denser and more durable microstructure with enhanced interfacial bonding, as confirmed by the microstructure study. According to this study, the most effective doses for enhancing UHPGC performance in various aspects are 2.5% NS and 4% NT. The CS was recorded at 198.7 MPa for 2.5% NS mixes and 197.6 MPa for 4% NT mixes for ages test 28 days. These findings provide valuable insights into developing and utilizing advanced, high-efficiency UHPGC for sustainable and sturdy construction techniques.

The main purpose of this research is to examine the performance of lightweight concrete (LWC) that contains palm oil clinker (POC) as a replacement for aggregate by either 50 or 100% of volume. Also, the use of palm oil ash (POA) and silica fume (SF) as a 10 and 20% weight replacement for cement, respectively, was examined. This research involved designing 20 mixtures. The performance of the fresh mixed LWC was assessed using a slump test. A variety of experiments were used to assess the performance of hardened concrete, including a dry density test, a compressive strength (CS) test, a split tensile strength test, a flexural strength test, and a modulus of elasticity test. In addition, the performance of concrete exposed to high temperatures on CS is evaluated. The transport properties were evaluated by applying tests including water permeability, chloride permeability, and water absorption. Finally, microstructure analysis was performed. The findings revealed that employing cementitious materials, such as SF and POA, as cement replacements or POC as an aggregate substitute reduced workability. The usage of POC as an alternative to aggregate also reduced CS. The mixture containing 100% POC showed the highest reduction, with a rate of 52% lower than the reference mixture. Furthermore, the applied temperature increased to 600°C, resulting in a significant decrease in CS, ranging from 34.6 to 42.6%.