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Influence of fiber types on the properties of the artificial cold-bonded lightweight aggregates

  • Hawraa Ahmed Sabr EMAIL logo and Waleed A. Abbas
Published/Copyright: February 22, 2024
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Open Engineering
From the journal Open Engineering Volume 14 Issue 1

Abstract

The cold-bonded pelletizing method is often employed in aggregate production since it uses less energy and helps reduce issues with gas emissions, contributing to economic and environmental benefits. In this study, fly ash was chosen as the raw material and used to partially replace cement in manufacturing artificial aggregate. Three types of fibers (polypropylene, polystyrene, and glass fiber) in different volume fractions were used to investigate their effect on the properties of the artificial cold-bonded lightweight aggregate. After the manufacturing process, aggregates were cured with a 28-day water curing. Their specific gravity, water absorption, density, impact value, and crushing value were tested to analyze the properties of the cold-bonded artificial aggregate. Results show that adding various volume fractions of PS, glass, and PP fibers during pelletization caused a more stable generation of aggregates with enhanced mechanical and physical properties.

Keywords: lightweight aggregates; cold-bonded; specific gravity; water absorption; crushing strength

1 Introduction

Lightweight aggregate concrete (LWAC) has been effectively employed for structural purposes for many years and has become a very convenient alternative to conventional concrete. The utilization of lightweight aggregates (LWAs) is a common practice in the production of concretes with reduced density. This approach offers several benefits, such as reducing the self-weight of structures and improved thermal insulation compared to normal-weight concrete. The low weight of the aggregate can be attributed to its cellular or highly porous microstructure [1]. Artificial LWA is made from waste materials, including fly ash (FA), ground granulated blast furnace slag (GGBFS), silica fume, and others, and it has a bright future because of rising interest and demand for it as a recyclable waste product [2]. The utilization of FA can further be increased in cold bonded aggregate concrete by using FA as a partial replacement for cement or sand. In general, artificial aggregate production involves the initial process of agglomerating powdered waste materials into newly formed pellets of the desired size. Subsequently, the recently produced pellets undergo autoclaving, sintering, or cold bonding techniques to achieve practical hardening [3].

FA and binder are mixed consistently during the cold bonding process. The amounts of FA and binder are well mixed. Water is added to the mixture in a pelletizer, thoroughly mixed, and FA aggregate is produced. This process of generating aggregates is known as palletization [4]. Remarkable waste treatment outcomes in manufacturing stabilized aggregates may be seen via the cold-bonding process, and the aggregates can be used in various construction applications. As a result, the process complies with the demands of the present world for waste disposal methods that are more environmentally friendly, and it can be entirely attributed to new technologies motivated by the circular economy principle [5].

Several recent studies have investigated cold-bonding pelletization processes to determine optimal operating conditions. The strength characteristics of ecologically friendly cold-bonded and sintered FA aggregate, GGBFS, and quartz LWAs were investigated by Ibrahim and Atmaca [6]. The obtained density outcomes concur with the established European regulations stipulating that the aggregate density must not surpass 2,000 kg/m3. Additionally, the FA mixtures exhibited the highest crushing strength. Applying mechanical activation treatment resulted in the production of finer FA, which led to a significant enhancement in pelletization efficiency, reaching up to 98%. The activated ash exhibited a higher specific surface area of 621.15 m2/kg and a lower mean particle diameter of 3.35 μm, resulting in a 33% increase in the average crushing value of the aggregate. Additionally, the activated ash was reduced by roughly 30% in water absorption and porosity, as reported by Anja Terzić et al. [7].

Adjusting and enhancing the aggregate qualities is motivated by a constant demand for stronger and lighter materials. The brittleness of LWA contributes to the reduced tensile and flexural strength of LWAC. This disadvantage can be overcome by utilizing an appropriate amount of fiber. Fiber reinforcement, in general, can improve the characteristics of ductile materials like concrete [8]. Multiple categories of cold-bonded LWAs, reinforced with fibers, were produced utilizing distinct binding agents, incorporating varying proportions of glass fibers (0, 0.17, and 0.34%) relative to the overall weight of materials during palletization. According to the outcomes of physical and mechanical properties testing, it has been determined that the most favorable amount of glass fibers to be added to artificial LWAs was 0.17% [9].

In contemporary times, there has been a surge in the popularity and commercial demand for LWAs across various construction applications. According to Cheeseman et al. [10], these aggregates present significant economic and environmental advantages due to their reduced density and thermal conductivity compared to traditional aggregates. LWAs could exist naturally or artificially. The utilization of natural aggregates has emerged as a controversial topic owing to their excessive consumption and the scarcity of natural reserves in numerous regions [11]. As a result, there has been a significant increase in the application of artificial LWAs in diverse construction materials. LWAs could be produced through cold bonding or sintering processes. The utilization of the sintering process is associated with two primary drawbacks, namely, substantial energy consumption and the discharge of significant volumes of pollutants, as reported by Harikrishnan and Ramamurthy [12].

Conversely, the cold bonding technique exhibits the possibility of being a good approach from both economic and environmental standpoints, provided that the prerequisites for density and strength could be enhanced, owing to its potential for reduced energy consumption. In recent years, academic research has significantly focused on producing LWAs using cold-bonding techniques. Numerous research endeavors have been directed toward recycling various by-products or waste materials as LWAs without regard to the density of the resultant aggregates.

In their study, Gesoğlu et al. [13] successfully constructed a cold-bonded aggregate utilizing GGBFS during production, resulting in a specific gravity of 2.14 g/cm. In their study, Kumar et al. [14] employed varying ratios of cement and FA, along with aggregates possessing specific gravity values ranging from 1.72 to 1.97 g/cm3, which were dependent on the cement content. According to Chi et al. [15], LWAs can be manufactured using FA and cement, resulting in an oven-dry specific gravity ranging from 1.23 to 1.44 g/cm3 and a particle strength of 6.04–8.57 MPa. A cold-bonded quarry dust coarse aggregate with a specific gravity of 1.9–2.5 g/cm3 has been developed by Thomas and Harilal [16]. This particular gravity is comparable to that of a normal-weight aggregate.

Colangelo and Cioffi [17] utilized GGBFS, cement kiln dust, and marble sludge in their manufacturing process. The produced aggregate exhibited a dry density of 1.7–1.98 g/cm3. The elevated density of cold-bonded LWAs compared to prevalent sintered LWAs like expanded clay and expanded glass is considered a primary drawback. Insufficient consideration has been given to this crucial matter, limiting the pragmatic utilization of cold-bonded LWAs.

In a recent study, Hwang and Tran [18] utilized hydrogen peroxide as a foaming agent to induce the formation of additional pores within the aggregate to decrease its density. According to the study, a foaming agent concentration of 7 wt% in conjunction with a composition of 80 wt% FA and 20 wt% GBFS resulted in a minimum oven-dry specific gravity of 1.27 g/cm3. Despite implementing this methodology resulting in a reduction in the particle density of low water absorption LWAs bonded at low temperatures, it remained comparatively greater than that of LWAs that are fused. To meet the three primary requirements of low particle density, favorable mechanical properties, and efficient waste material recycling, a new method of cold-bonded production is necessary.

The primary aims of this study can be delineated as follows:

The present study aims to enhance the efficiency of a cold-bonded technique in synthesizing artificial LWAs characterized by reduced density and superior mechanical characteristics. The current investigation involves the production of a LWA featuring a core-shell structure. This was achieved by encapsulating fibers within a cement and FA cover matrix. In addition, the study aims to examine the impact of various fibers on the aggregate properties to identify the optimal values of these parameters. Finally, the implementation of fibers has been proposed as a viable approach to mitigating the particle density of the produced aggregate, resulting in a value below 2 g/cm3 reduction. To accomplish these goals, fibers were integrated into the shell architecture. Several tests were performed to assess the impact of fiber content on the mechanical and microstructural characteristics of the produced aggregate.

2 Methodology

The production of LWAs was achieved through the process of encapsulating fibers within a shell structure, as illustrated in Figure 1. The encapsulation process was executed utilizing a pelletizer disc with a diameter of 80 cm and a depth of 35 cm, as depicted in Figure 2. The present investigation involved the production of four distinct sets of LWAs. The initial cluster involved the encapsulation of polystyrene (PS) fibers, which varied in size from 2 to 3 mm, within a cover matrix consisting of cement and FA. A set of 40 samples was generated, each exhibiting varying percentages of three distinct fiber types: polypropylene (PP), PS, and glass fiber (Figure 3).

Figure 1 Formation of artificial PS fiber-reinforced cold-bonded LWA.
Figure 1

Formation of artificial PS fiber-reinforced cold-bonded LWA.

Figure 2 Pelletization disc.
Figure 2

Pelletization disc.

Figure 3 Types of fibers used: (a) PS fibers, (b) PP fibers, and (c) glass fibers.
Figure 3

Types of fibers used: (a) PS fibers, (b) PP fibers, and (c) glass fibers.

The aggregate’s performance was assessed through standardized tests to determine the most favorable values for said parameters. Subsequently, within the subsequent cohort, the production procedure involved the inclusion of PP fibers measuring 6 mm in length. The material earlier was employed in the FA and cement covering matrix. The manufacturing process involved incorporating a third group of glass fibers, which had a length of 6 mm. The cover matrix utilized in the study consisted solely of FA and cement, excluding fibers, as observed in the FA and cement cover matrix. The determined values of angle, speed, and water content were held constant while other parameters were varied. Several tests were performed to assess the impact of fibers on the characteristics of the aggregate.

3 Research significance

The increasing awareness of environmental concerns and the desire to conserve depleted natural resources, which have been impacted by the industrial revolution across multiple sectors, including construction, has led to the emergence of a concept involving utilizing FA in producing artificial aggregate through recycling. The utilization of aggregates in concrete is known to occupy a significant volume. However, producing artificial aggregates through the cold-bonding process using minerals such as these and their subsequent incorporation into concrete production may be a viable strategy for promoting the recycling of waste materials.

Incorporating fibers at various volume fractions could improve the properties of artificial cold-bonded aggregates. The present study comprehensively analyzes artificially reinforced cold-bonded LWA’s different mechanical and durability characteristics. The current study examined the physical and mechanical properties of materials bonded through cold-bonding techniques. This study evaluated the impact of fiber incorporation on the simplified strength characteristics of artificial cold-bonded LWAs. The study also examined the effect of water-curing techniques on the strength-gain characteristics of different artificial LWAs.

4 Experimental methods

4.1 Materials

4.1.1 Cement

The study employed Portland cement, comparable to the limits of IQS. No. 5/1984. The cement had a Blaine fineness of 3,430 c m2/g and a specific gravity of 3.17. This type of cement is composed of a notably higher proportion of silicate compounds. The material exhibits a moderate fineness, rendering it suitable for optimal application scenarios, and demonstrates a satisfactory level of hydration heat release, ensuring safety during use. Table 1 presents the chemical compositions of the Portland cement employed in the current research.

Table 1

Chemical composition and physical properties of FA and Portland cement

%Chemical analysis FA Portland cement
SiO2 56.2 20.25
CaO 24 1.9 62.58
Fe2O3 6.69 4.04
Al2O3 15.2 5.31
SO3 0.49 2.73
MgO 1.7 2.82
Na2O 0.58 0.22
K2O 1.89 0.92
Specific gravity 2.2 3.1
Loss on ignition 1.78 1.02

4.1.2 FA

The present investigation employed class F FA that adhered to the standards of ASTM C 618 [19] to fabricate cold-bonded and sintered artificial FA aggregates. The FA exhibits a specific surface area of 287 m2/kg and a specific gravity of 2.25. The physical and chemical characteristics of the FA utilized are presented in Table 1.

4.1.3 Fibers

Three types of fibers were utilized in artificial LWA production; their properties are displayed in Table 2.

Table 2

Properties of PS, PP, and glass fibers

Property PS PP Glass fiber
Diameter (µm) 700–900 32 13
Density (kg/m3) 600 910 2,560
Tensile modulus (GPa) 2–4.5 0.8–1.4 76
Tensile strength (MPa) 32.4–56.5 25–38 3,445
Elongation (%) 1.2–3.6 300 2.75
Thermal conductivity (W/m/°C) 0.12 Low 1.3
Specific heat (J/kg/°K) 1.68 1.85 0.8
4.1.3.1 PS fibers

Expandable PS was used with good foaming capacity, energy-saving processing, and a short cycle time.

4.1.3.2 PP fibers

Monofilament PP fibers for explosive spalling protection from the SikaFiber® trademark with a 6 mm length were utilized.

4.1.3.3 Glass fibers

E-glass, also known as electrical glass (G) fibers, was used. It is made from silicon, aluminum, calcium, magnesium, and boron oxides.

4.2 Preparation of lightweight artificial aggregate using the cold-bonding method

The production of LWA involved the incorporation of three distinct fiber varieties within a cover matrix consisting of cement and FA, which was executed through a pelletization disc. The process of producing LWAs reinforced with fiber was carried out through the pelletization technique, as depicted in Figure 1. A disc pelletizer with dimensions of 800 mm in diameter and 350 mm in depth was constructed, utilizing a cement-to-FA ratio of 20:80. The optimal conditions for achieving maximum efficiency in the production of aggregates were determined through various experiments. Expressly, the inclination angle and speed were set at 45° and 11 rpm, respectively, while maintaining a constant pelletization time of 17 min. During the initial 8-min period, approximately 28% of the water was dispersed onto the materials to facilitate spherical ball formation. An additional duration of 9 min was allocated to reinforce the stiffness of the pellets to improve their bonding properties.

Fibers were incorporated into the sample at volumetric concentrations of 0.1, 0.2, and 0.3%. Initially, the disc pelletizer was charged with a composite of FA and cement, which was subsequently blended uniformly for 2 min. Fibers were introduced into the mixture and stirred for an additional 1 min. Later, the necessary proportion of water, amounting to 28%, is dispersed through spraying. The encapsulation process involved carefully spraying water while simultaneously feeding powder into the disc, facilitating the uninterrupted continuation of pelletization. In this process, the size of the pellets increases over time until a certain point is reached, beginning with a small initial size. Finally, after pelletization was finished, the disc was emptied of its new pellets. Upon completion of the manufacturing process, the newly produced pellets exhibit a size distribution ranging from 4 to 12.5 mm and possess a shape that closely approximates a sphere. The specimens were subjected to a 24-h air-drying process, after which they underwent a cold-bonding process (water curing) for 28 days at an ambient temperature of approximately 23°C for pellet hardening, as depicted in Figure 1 (Figures 4 and 5).

Figure 4 Cold-bonding manufacturing process.
Figure 4

Cold-bonding manufacturing process.

Figure 5 Hardening and curing the artificial aggregate.
Figure 5

Hardening and curing the artificial aggregate.

4.3 Applied test methods

4.3.1 Physical properties investigations properties of cold-bonded aggregates

The physical parameters of the artificial aggregates were determined by conducting tests to measure their specific gravity, water absorption, and bulk density after the pellets had cured for 28 days in line with ASTM C127 [20] and ASTM C29/C29M [21]. The test specimen comprises aggregates segregated into distinct size fractions ranging from 4 to 12.5 mm through sieving.

4.3.1.1 Specific gravity test

Determining the specific gravity of aggregate is established as the proportion of the weight of the solid component within a specified volume of the sample to the weight of an equivalent volume of water at an exact temperature.

4.3.1.2 Water absorption test

The phenomenon of water absorption refers to the rise in the mass of aggregate caused by the water penetration into the pores of the particles within a specified time frame while excluding any water that may be adhering to the external surface of the particles. This experiment aims to ascertain how much aggregate changes in mass are due to water absorption within its pores.

The procedure outlined in ASTM C127 was employed, wherein a quantity of 2 kg of LWA was subjected to washing and drying before being placed in an oven set to a temperature of 105 ± 5°C for 1–3 h to prepare the test sample. Subsequently, the sample was allowed to reach ambient temperature before handling. After that, the specimens were submerged at ambient temperature for 24 ± 4 h. The test specimens were removed from the water bath and then dried by wiping until complete saturation and dryness of its surface were achieved. Subsequently, the mass of the low-density material was measured and documented as variable B. Finally, the LWA was placed in an oven at 105 ± 5°C for 24 ± 4 h. The resulting weight of the LWA is then measured and documented as A.

(1) % Absorption = B − A A × 100 % .

4.3.1.3 Loose bulk density (LBD) test

The aggregate’s LBD (q), which was found to be smaller than the maximum size of 37.5 mm, was assessed following the established ASTM C29/C29M regulations. The LBD refers to the quantity of non-compacted aggregates necessary to occupy a container of a standardized volume after the batching of aggregates based on volume. The artificial aggregates that were produced were assessed through the use of a balance and a measuring cylinder. Initially, the mass of the aggregate (m) was determined. Subsequently, a suitable quantity of water was introduced into the measuring cylinder, and the volumetric measurement of the water (V 1) was documented. Later, the synthetic aggregate was affixed to a thin string and situated within a graduated cylinder filled with water (ensuring complete submersion) to ascertain the water volume (V 2). The calculation of bulk density was derived by utilizing the following equation (Figure 6):

(2) q = m V 2 − V 1 .

Figure 6 Physical properties testing process.
Figure 6

Physical properties testing process.

4.3.2 Mechanical properties investigations properties of cold-bonded aggregates

4.3.2.1 Impact value test

The aggregate impact value (AIV) measures resistance to sudden impact, which may differ from resistance to a gradually applied compressive load. Impact value was carried out per BS 812-112:1990 [22] after the pellet was cured for 28 days (Figure 7).

(3) AIV = W 2 W 1 × 100 ,

where W 1 is the weight of the FA LWA sample, and W 2 is the weight of fractions passing 2.36 mm sieve size.

Figure 7 Impact value testing process.
Figure 7

Impact value testing process.

4.3.2.2 Crushing strength test

The procedure for conducting crushing strength (σ) testing was executed in accordance with the guidelines outlined in BS 812, Part 110.24 [23]. In this study, pellets of varying sizes ranging from 4 to 12 mm were subjected to a 28-day curing process (equivalent to 0.24–0.47 inches). The California bearing ratio was utilized to estimate individual artificial aggregates’ compressive strength. This was achieved by subjecting them to a diametrical loading test between two parallel plates until failure was observed (Figure 8, Table 3).

(4) σ = 2.8 × P Pie × d 2 .

Figure 8 Crushing strength testing process.
Figure 8

Crushing strength testing process.

Table 3

Properties specification of the produced LWA

Properties Specification
Specific gravity ASTM C127
Absorption ASTM C127
Dry LBD ASTM C 29
Aggregate crushing value BS 812-part 110-1990
AIV BS 812- part 112-1990

5 Results and discussion

The aggregate characteristics of the generated FA aggregates were evaluated as per the previous section. The aggregate characteristics for various kinds of fiber and volume fractions have been documented in the subsequent sections based on the obtained results.

5.1 Specific gravity

Table 4 displays the diverse levels of saturated surface dryness observed in the LWAs. The research results indicate that an increase in the quantity of cement leads to a corresponding rise in the specific gravity of LWA. Portland cement’s higher specific gravity than FA and fibers explains this effect. Table 2 shows that the specific gravity of aggregates made with a cement-FA binder and 0.3, 0.2, or 0.1% PS fiber was less than that of aggregates made with the same volume fraction of PP or glass.

Table 4

Physical and mechanical properties of cold-bonded artificial aggregates

Mix ID Specific gravity Water absorption (%) Bulk density (kg/m3) Impact value (%) Crushing strength (MPa)
Control 1.97 15 896 28.1 14.9
LWA-0.1PS 1.28 32 619 30.8 12
LWA-0.2PS 1.26 34 610 29.8 10
LWA-0.3PS 1.24 36 600 34.7 9
LWA-0.1PP 1.86 24.7 879 20.7 16
LWA-0.2PP 1.88 22.6 881 19.5 17.2
LWA-0.3PP 1.89 20.5 883 16.7 18.2
LWA-0.1G 1.74 30.5 860 29.4 15.2
LWA-0.2G 1.75 29.5 861 28.3 16.5
LWA-0.3G 1.76 28.8 863 28.7 16.9

This is due to the lower density of this fiber. It was also noted that reinforced aggregate with a volume fraction of 0.3% PS has the lowest specific gravity compared with volume fractions of 0.2 and 0.1%. However, in the case of LWAs reinforced with PP, the specific gravity of LWAs was the highest compared to the other types of LWA reinforced with glass and PS, and the volume fraction of 0.3% (PP) caused a marked increase in the specific gravity of LWAs compared to the other volume fractions (0.2, 0.1%), the content of the PP (0.3%) was greater, so it was packing the pellet with more content than the other percentage, making the specific gravity values higher, and the density of aggregate was high.

In the case of LWA reinforced with glass fiber, the specific gravity values were lower than those of PP, and we can observe that volume fraction (0.3%) gives a high specific gravity when compared with 0.2 and 0.1%. It was noted that when decreasing the percentage of fibers, the specific gravity of LWAs in the case of glass and PP fibers decreased due to their content and specific gravity. In contrast, when PS fiber decreased the percentage of fiber, the specific gravity of LWAs increased because when the beads took up more space in the pellet, the specific gravity values were lower (Figure 9).

Figure 9 Specific gravity of fiber-reinforced cold-bonded LWAs.
Figure 9

Specific gravity of fiber-reinforced cold-bonded LWAs.

5.2 Water absorption

Based on the experimental results, the 24-h water absorption values of various artificial aggregates made with FA and Portland cement were plotted as shown in Figure 10. It was observed that there was a rise in the water absorption of LWAs reinforced with PS and volume fraction (0.3, 0.2, and 0.1%) compared to the other types of LWAs reinforced with glass and PP. Higher water absorption can be attributed to the higher porosity of the aggregates manufactured with PS, which, in order to make the PS aggregate lighter, the highest water absorption was observed for the volume fraction of 0.3% due to the high content and the low specific gravity as well as the low strength that make the porosity high. The lowest water absorption was observed for LWAs reinforced with PP with a 0.3% volume fraction. The aggregate becomes denser due to discontinuous porosity and small pore sizes. For the glass aggregate, it was also noted that there is a rise in water absorption due to porosity. It was recognized from the test results that the water absorption values of different aggregates follow the porosity, and it was examined that for aggregate manufactured with PS, the porosity decreased with decreased volume fraction.

Figure 10 Water absorption of fiber-reinforced cold-bonded LWAs.
Figure 10

Water absorption of fiber-reinforced cold-bonded LWAs.

In contrast, the porosity increased with a decreased volume fraction in the case of aggregate manufactured with PP or glass. Higher water absorption with high porosity is connected with the decreased stiffness of artificial aggregates, which leads to high shrinkage in lightweight concrete (Gesoglu et al. [24]). Adding fibers shows a significant reduction in water absorption as the percentage of fiber decreases to 0.1% in the case of PS and increases in the cases of glass and PP as the percentage decreases due to the content that affects the porosity.

5.3 Bulk density

Table 2 presents the LBD outcomes of artificial LWAs reinforced with fibers, produced using varying volume fractions. The results indicate that increased bulk density was observed in LWA reinforced with PP at varying volume fractions. In contrast, a decreased bulk density was observed in LWA produced with PS at varying volume fractions. According to Chi et al. [25], the higher bulk density observed during pelletization can be attributed to the favorable pore structure, consequently reducing water absorption.

In addition, it was observed that including fiber at a higher concentration (0.3%) reduced bulk density for PS aggregate. In contrast, for glass and PP aggregate, the bulk density lowered as the fiber percentage decreased, owing to the high density of these fibers. The study revealed that the bulk density of LWAs produced using PP was comparatively greater. The findings indicate that the introduction of PS fibers at a concentration of 0.3% resulted in a reduction in bulk density. The incorporation of PP and glass fibers at a concentration of 0.1% was observed (Figure 11).

Figure 11 Bulk density of fiber-reinforced cold-bonded LWAs.
Figure 11

Bulk density of fiber-reinforced cold-bonded LWAs.

5.4 Impact value

Figure 12 presents the impact strength test outcomes of artificial aggregates reinforced with different fibers. The impact strength of various LWAs depends on the binder utilized and the proportion of fiber added. Specifically, an investigation has revealed that LWA produced with PP at volume fractions of 0.3, 0.2, and 0.1% exhibits the lowest impact strength. In contrast, LWA manufactured with PS at the same volume fractions demonstrates the highest impact strength. The observed outcome resulted in an augmentation of the bonding characteristics, concomitant with an elevation in the microstructural features.

Figure 12 Impact value of fiber-reinforced cold-bonded LWAs.
Figure 12

Impact value of fiber-reinforced cold-bonded LWAs.

The study revealed that a decrease in the percentage of PS fiber resulted in a corresponding reduction in impact values. Conversely, a decrease in the percentage of PP and glass led to an increase in impact values. The observation was made that the impact strength is contingent upon the binder utilized during the pelletization process, as it contributes to enhancing properties through microstructure formation. The findings suggest that an increase in the proportion of glass and PP fibers leads to a decrease in impact values. Conversely, an increase in the proportion of PS increased impact values.

5.5 Crushing strength

Table 2 displays the experimental results of the compressive strength of discrete aggregate components fortified with fibers within the framework of synthetic aggregates. The investigation analyzed the potency evaluation of the fiber category and the ratio of fibers incorporated. It has been observed that an increase in the percentage of fiber in PS by 0.3% results in a decrease in crushing strength compared to percentages of 0.2 or 0.1. Conversely, in the case of PP and glass, an increase in the percentage of fiber by 0.3 leads to an increase in crushing strength when compared to percentages of 0.2 or 0.1. The study revealed that the PP aggregate exhibited the highest crushing strength owing to its dense structure. In contrast, the PS aggregate demonstrated the lowest crushing strength due to its weak fiber strength and structure.

6 Morphology

6.1 Morphology

The morphology of LWAs can be examined via scanning electron microscopy (SEM). The present study employed SEM to examine a lightweight artificial aggregate produced from FA and cement. The aggregate was further reinforced with PS, PP, and glass fibers at a volume fraction of 0.3%. The microstructure of the 28-day-old aggregate was analyzed using SEM to investigate the impact of fibers. SEM was utilized to examine the fracture surface of synthetic aggregates of a uniform size of 1 cm. Before analysis, the aggregates were subjected to an oven at 105 ± 5°C for 24 h to remove any evaporation of water content. The samples were then mounted on alloy stubs and underwent sputtering physical and chemical interfacial action [1]. In cases where the sample was not electrically conducting, a carbon or gold coating was required. Typically, a carbon coating was applied to obtain clear images before the samples were subjected to electron scanning.

Two specimens were used for the scanning electron microscope evaluations:

The study employed LWA0 as a control devoid of fibers, while PSLWA, GLWA, and PPLWA were utilized as experimental groups with varying types of fibers. Figure 12a–d depict the SEM images of LWA, PSLWA, GLWA, and PPLWA. Typically, the aggregate generated comprises three distinct structures: a honeycomb core structure consisting of fibers, a porous shell structure comprising cement and FA, and a transition zone that interfaces between the core and shell structures. Figure 13 compares the shell microstructure between LWA0 and three types of LWA, namely PSLWA, GLWA, and PPLWA. In the case of LWA0, it was observed that there were no remaining FA particles that exhibited any signs of reactivity, as depicted in Figure 13a. Furthermore, it is possible to distinctly differentiate the presence of ettringite and calcium hydroxide crystals (CH) on the FA particles’ surface.

Figure 13 Crushing value of fiber-reinforced cold-bonded LWAs.
Figure 13

Crushing value of fiber-reinforced cold-bonded LWAs.

Thus, it can be deduced that a reduced pozzolanic reaction rate might have occurred within the covering matrix of the LWA0. Conversely, Figure 13b–d demonstrates a distinct alteration in microstructure resulting from including fibers in PPLWA, PSLWA, and GLWA instances. The observation can be made that the existence of voids in the morphology indicates that the creation of voids plays a role in reducing the specific density and increasing the LBD of the cold-bonded reinforced LWA. The presence of fibers in the development of pores in the aggregates PSLWA, PPLWA, and GLWA results in a notable increase in pore size, forming a porous aggregate structure. The experiment yielded the formation of various substances, including calcium hydroxide crystals (portlandite), ettringite in the form of long and slender needles, crystals of C–S–H, and a significant quantity of hydration products.

The results above suggest that the pozzolanic reaction experienced a noteworthy increase in pace within the covering matrix of PPLWA, PSLWA, and GLWA. Utilizing a composite material consisting of FA and cement, supplemented with 0.3% fibers, results in greater porosity within the aggregate. Moreover, Figure 14 assesses the interfacial transition zone (ITZ) between the core, consisting of fibers, and the shell structures, comprising FA and cement. The inadequate formation of hydration products leads to a feeble transition zone in PPLWA, PSLWA, and GLWA, as depicted in Figure 14a. The densification of the PPLWA, PSLWA, and GLWA transition zones was effectively contributed by the growth of pozzolanic reaction products on the core structure’s surface, as demonstrated in Figure 14b–d. The SEM observations validate that the inclusion of fibers has enhanced the microstructure of the resultant aggregate. This phenomenon could elucidate the impact of fibers on augmenting the 28-day compressive strength, despite their involvement in reducing the particle density (Figures 15 and 16).

Figure 14 SEM Images of the cross-section of LWA: (a) Reference, (b) PS, (c) glass, and (d) PP.
Figure 14

SEM Images of the cross-section of LWA: (a) Reference, (b) PS, (c) glass, and (d) PP.

Figure 15 SEM Images of the shell structure of LWA: (a) Reference, (b) PS, (c) glass, and (d) PP.
Figure 15

SEM Images of the shell structure of LWA: (a) Reference, (b) PS, (c) glass, and (d) PP.

Figure 16 SEM Images of the ITZ of LWA: (a) Reference, (b) PS, (c) glass, and (d) PP.
Figure 16

SEM Images of the ITZ of LWA: (a) Reference, (b) PS, (c) glass, and (d) PP.

7 Conclusion

The following implications are made in light of the findings of the current research:

  1. Incorporating PS, glass, and PP fibers at varying volume fractions during pelletization resulted in aggregates exhibiting enhanced physical and mechanical properties, ensuring greater stability during production.

  2. The specific gravity value was higher for the reference aggregate (without fiber) and lowest for the aggregate reinforced with fibers.

  3. The results indicate that the PS aggregate exhibited the lowest specific gravity values, while the PP aggregate exhibited the highest specific gravity values among the fiber-reinforced aggregates. Also, as the fiber content increases for the PS, the specific gravity decreases, the water absorption increases, and the bulk density decreases.

  4. The study reports that the aggregate produced exhibited a particle density and LBD within the range of 1.2–1.9 and 600–900 g/m3, respectively. Additionally, the bulk crushing strength of the aggregate was found to be within the range of 8–14 MPa.

  5. As the fiber content increases for the glass and PP, the specific gravity increases, the water absorption decreases, and the bulk density increases.

  6. The impact value was higher with the increase in PS fiber content; however, it was higher with the decrease in glass and PP fiber content.

  7. The highest crushing strength was noticed for the glass and PP fiber aggregate, and the lowest crushing strength was noticed for the aggregate manufactured with PS fiber.

  8. It was found that when the percentage of fiber increases for the PS aggregate, the crushing strength decreases, and when the percentage of fiber increases for the glass and PP aggregates, the crushing strength increases due to the effect of fiber that stiffens the aggregate.

  1. Funding information: We declare that the manuscript was done depending on the personal effort of the author, and there is no funding effort from any side or organization.

  2. Conflict of interest: The authors state no conflict of interest.

  3. Data availability statement: Most datasets generated and analyzed in this study are in this submitted manuscript. The other datasets are available on reasonable request from the corresponding author with the attached information.

References

[1] Kumar R, Srivastava A. Influence of lightweight aggregates and supplementary cementitious materials on the properties of lightweight aggregate concretes. Iran J Sci Technol - Trans Civ Eng. 2022;5:1–27. 10.1007/s40996-022-00935-5.Search in Google Scholar

[2] Ibrahim MA, Atmaca N, Abdullah AA, Atmaca A. Mechanical properties of concrete produced by light cement-based aggregates. Sustainability. 2022;14:1–17. 10.3390/su142315991.Search in Google Scholar

[3] Tajra F, Elrahman M, Stephan D. The production and properties of cold-bonded aggregate and its applications in concrete: A review. Constr Build Mater. 2019;225:29–43. 10.1016/j.conbuildmat.2019.07.219.Search in Google Scholar

[4] Mohan A, Dr. Vasudev R. Artificial lightweight aggregate through cold bonding pelletization of fly ash: A review. Int Res J Eng Technol. 2018;5:778–83.Search in Google Scholar

[5] Ferraro A, Colangelo F, Farina I, Race A, Cioffi R, Cheeseman C, et al. Cold-bonding process for treatment and reuse of waste materials: Technical designs and applications of pelletized products. Crit Rev Environ Sci Technol. 2020;51:1–35. 10.1080/10643389.2020.1776052.Search in Google Scholar

[6] Ibrahim MA, Atmaca N. Cold bonded and low-temperature sintered artificial aggregate production by using waste materials. Period Polytech Civ Eng. 2023;67:112–22. 10.3311/PPci.20885.Search in Google Scholar

[7] Anja Terzić A, Pezo L, Mitić V, Radojević Z. Artificial fly ash based aggregates properties influence on lightweight concrete performances. Ceram Int. 2015;41:2714–26. 10.1016/j.ceramint.2014.10.086.Search in Google Scholar

[8] Libre NA, Shekarchi M, Mahoutian M, Soroushian B. Mechanical properties of hybrid fiber reinforced lightweight aggregate concrete made with natural pumice. Constr Build Mater. 2011;25:2458–64. 10.1016/j.conbuildmat.2010.11.058.Search in Google Scholar

[9] Vali KS, Murugan SB. Properties of glass fiber reinforced cold bonded lightweight artificial aggregate with different binders. Rom J Mater. 2020;50:40–50.Search in Google Scholar

[10] Cheeseman CR, Makinde A, Bethanis S. Properties of lightweight aggregate produced by rapid sintering of incinerator bottom ash. Resour Conserv Recycl. 2005;43(2):147–62. 10.1016/j.resconrec.2004.05.004.Search in Google Scholar

[11] Kockal NU, Ozturan T. Microstructural and mineralogical characterization of artificially produced pellets for civil engineering applications. J Mater Civ Eng. 2017;29(2):4016214. 10.1061/(ASCE)MT.1943-5533.0001739.Search in Google Scholar

[12] Harikrishnan KI, Ramamurthy K. Influence of pelletization process on the properties of fly ash aggregates. Waste Manag. 2006;26(8):846–52. 10.1016/j.wasman.2005.10.012.Search in Google Scholar

[13] Gesoğlu M, Güneyisi E, Mahmood SF, Öz HÖ, Mermerdaş K. Recycling ground granulated blast furnace slag as cold bonded artificial aggregate partially used in self-compacting concrete. J Hazard Mater. 2012;235:352–8. 10.1016/j.jhazmat.2012.08.013.Search in Google Scholar

[14] Kumar VRP, Anandh K, Kumar M. An experimental study on partial replacement of natural coarse aggregate with fly ash coarse aggregate (FACA). Res Appl Sci Eng Tech. 2014;2:212–23.Search in Google Scholar

[15] Chi JM, Huang R, Yang C-C, Chang JJ. Effect of aggregate properties on the strength and stiffness of lightweight concrete. Cem Concr Compos. 2003;25(2):197–205. 10.1016/S0958-9465(02)00020-3.Search in Google Scholar

[16] Thomas J, Harilal B. Properties of cold bonded quarry dust coarse aggregates and its use in concrete. Cem Concr Compos. 2015;62:67–75. 10.1016/j.cemconcomp.2015.05.005.Search in Google Scholar

[17] Colangelo F, Cioffi R. Use of cement kiln dust, blast furnace slag and marble sludge in the manufacture of sustainable artificial aggregates by means of cold bonding pelletization. Materials (Basel). 2013;6(8):3139–59. 10.3390/ma6083139.Search in Google Scholar

[18] Hwang C-L, Tran V-A. A study of the properties of foamed lightweight aggregate for self-consolidating concrete. Constr Build Mater. 2015;87:78–85. 10.1016/j.conbuildmat.2015.03.108.Search in Google Scholar

[19] A. C. 618. Specification for fly ash and raw or calcined natural puzzolan for use as a mineral admixture in Portland cement concrete. Annual Book of ASTM, 2004.Search in Google Scholar

[20] ASTM C127-15 Standard test method for relative density (specific gravity) and absorption of coarse aggregate.Search in Google Scholar

[21] ASTM C29/C29M-97 Standard test method for bulk density (“unit weight”) and voids in aggregate.Search in Google Scholar

[22] BS 812-112: 1990 Testing aggregates Method for determination of aggregate impact value (AIV).Search in Google Scholar

[23] BS 812-110 Testing aggregates - Part 110: Methods for determination of aggregate crushing value (ACV).Search in Google Scholar

[24] Gesoğlu M, Özturan T, Güneyisi E. Shrinkage cracking of lightweight concrete made with cold-bonded fly ash aggregates. Cem Concr Res. 2004;34:1121–30. 10.1016/j.cemconres.2003.11.024.Search in Google Scholar

[25] Chi EY, Krishnan S, Randolph TW, Carpenter JF. Physical stability of proteins in aqueous solution: Mechanism and driving forces in nonnative protein aggregation. Pharm Res. 2003;20(2003):1325–36. 10.1023/A:1025771421906.Search in Google Scholar
Received: 2023-06-01
Revised: 2023-07-07
Accepted: 2023-07-17
Published Online: 2024-02-22

© 2024 the author(s), published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

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https://doi.org/10.1515/eng-2022-0498
Keywords for this article
lightweight aggregates; cold-bonded; specific gravity; water absorption; crushing strength
Creative Commons
BY 4.0

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  88. Deep learning techniques in concrete powder mix designing
  89. Effect of loading type in concrete deep beam with strut reinforcement
  90. Studying the effect of using CFRP warping on strength of husk rice concrete columns
  91. Parametric analysis of the influence of climatic factors on the formation of traditional buildings in the city of Al Najaf
  92. Suitability location for landfill using a fuzzy-GIS model: A case study in Hillah, Iraq
  93. Hybrid approach for cost estimation of sustainable building projects using artificial neural networks
  94. Assessment of indirect tensile stress and tensile–strength ratio and creep compliance in HMA mixes with micro-silica and PMB
  95. Density functional theory to study stopping power of proton in water, lung, bladder, and intestine
  96. A review of single flow, flow boiling, and coating microchannel studies
  97. Effect of GFRP bar length on the flexural behavior of hybrid concrete beams strengthened with NSM bars
  98. Exploring the impact of parameters on flow boiling heat transfer in microchannels and coated microtubes: A comprehensive review
  99. Crumb rubber modification for enhanced rutting resistance in asphalt mixtures
  100. Special Issue: AESMT-6
  101. Design of a new sorting colors system based on PLC, TIA portal, and factory I/O programs
  102. Forecasting empirical formula for suspended sediment load prediction at upstream of Al-Kufa barrage, Kufa City, Iraq
  103. Optimization and characterization of sustainable geopolymer mortars based on palygorskite clay, water glass, and sodium hydroxide
  104. Sediment transport modelling upstream of Al Kufa Barrage
  105. Study of energy loss, range, and stopping time for proton in germanium and copper materials
  106. Effect of internal and external recycle ratios on the nutrient removal efficiency of anaerobic/anoxic/oxic (VIP) wastewater treatment plant
  107. Enhancing structural behaviour of polypropylene fibre concrete columns longitudinally reinforced with fibreglass bars
  108. Sustainable road paving: Enhancing concrete paver blocks with zeolite-enhanced cement
  109. Evaluation of the operational performance of Karbala waste water treatment plant under variable flow using GPS-X model
  110. Design and simulation of photonic crystal fiber for highly sensitive chemical sensing applications
  111. Optimization and design of a new column sequencing for crude oil distillation at Basrah refinery
  112. Inductive 3D numerical modelling of the tibia bone using MRI to examine von Mises stress and overall deformation
  113. An image encryption method based on modified elliptic curve Diffie-Hellman key exchange protocol and Hill Cipher
  114. Experimental investigation of generating superheated steam using a parabolic dish with a cylindrical cavity receiver: A case study
  115. Effect of surface roughness on the interface behavior of clayey soils
  116. Investigated of the optical properties for SiO2 by using Lorentz model
  117. Measurements of induced vibrations due to steel pipe pile driving in Al-Fao soil: Effect of partial end closure
  118. Experimental and numerical studies of ballistic resistance of hybrid sandwich composite body armor
  119. Evaluation of clay layer presence on shallow foundation settlement in dry sand under an earthquake
  120. Optimal design of mechanical performances of asphalt mixtures comprising nano-clay additives
  121. Advancing seismic performance: Isolators, TMDs, and multi-level strategies in reinforced concrete buildings
  122. Predicted evaporation in Basrah using artificial neural networks
  123. Energy management system for a small town to enhance quality of life
  124. Numerical study on entropy minimization in pipes with helical airfoil and CuO nanoparticle integration
  125. Equations and methodologies of inlet drainage system discharge coefficients: A review
  126. Thermal buckling analysis for hybrid and composite laminated plate by using new displacement function
  127. Investigation into the mechanical and thermal properties of lightweight mortar using commercial beads or recycled expanded polystyrene
  128. Experimental and theoretical analysis of single-jet column and concrete column using double-jet grouting technique applied at Al-Rashdia site
  129. The impact of incorporating waste materials on the mechanical and physical characteristics of tile adhesive materials
  130. Seismic resilience: Innovations in structural engineering for earthquake-prone areas
  131. Automatic human identification using fingerprint images based on Gabor filter and SIFT features fusion
  132. Performance of GRKM-method for solving classes of ordinary and partial differential equations of sixth-orders
  133. Visible light-boosted photodegradation activity of Ag–AgVO3/Zn0.5Mn0.5Fe2O4 supported heterojunctions for effective degradation of organic contaminates
  134. Production of sustainable concrete with treated cement kiln dust and iron slag waste aggregate
  135. Key effects on the structural behavior of fiber-reinforced lightweight concrete-ribbed slabs: A review
  136. A comparative analysis of the energy dissipation efficiency of various piano key weir types
  137. Special Issue: Transport 2022 - Part II
  138. Variability in road surface temperature in urban road network – A case study making use of mobile measurements
  139. Special Issue: BCEE5-2023
  140. Evaluation of reclaimed asphalt mixtures rejuvenated with waste engine oil to resist rutting deformation
  141. Assessment of potential resistance to moisture damage and fatigue cracks of asphalt mixture modified with ground granulated blast furnace slag
  142. Investigating seismic response in adjacent structures: A study on the impact of buildings’ orientation and distance considering soil–structure interaction
  143. Improvement of porosity of mortar using polyethylene glycol pre-polymer-impregnated mortar
  144. Three-dimensional analysis of steel beam-column bolted connections
  145. Assessment of agricultural drought in Iraq employing Landsat and MODIS imagery
  146. Performance evaluation of grouted porous asphalt concrete
  147. Optimization of local modified metakaolin-based geopolymer concrete by Taguchi method
  148. Effect of waste tire products on some characteristics of roller-compacted concrete
  149. Studying the lateral displacement of retaining wall supporting sandy soil under dynamic loads
  150. Seismic performance evaluation of concrete buttress dram (Dynamic linear analysis)
  151. Behavior of soil reinforced with micropiles
  152. Possibility of production high strength lightweight concrete containing organic waste aggregate and recycled steel fibers
  153. An investigation of self-sensing and mechanical properties of smart engineered cementitious composites reinforced with functional materials
  154. Forecasting changes in precipitation and temperatures of a regional watershed in Northern Iraq using LARS-WG model
  155. Experimental investigation of dynamic soil properties for modeling energy-absorbing layers
  156. Numerical investigation of the effect of longitudinal steel reinforcement ratio on the ductility of concrete beams
  157. An experimental study on the tensile properties of reinforced asphalt pavement
  158. Self-sensing behavior of hot asphalt mixture with steel fiber-based additive
  159. Behavior of ultra-high-performance concrete deep beams reinforced by basalt fibers
  160. Optimizing asphalt binder performance with various PET types
  161. Investigation of the hydraulic characteristics and homogeneity of the microstructure of the air voids in the sustainable rigid pavement
  162. Enhanced biogas production from municipal solid waste via digestion with cow manure: A case study
  163. Special Issue: AESMT-7 - Part I
  164. Preparation and investigation of cobalt nanoparticles by laser ablation: Structure, linear, and nonlinear optical properties
  165. Seismic analysis of RC building with plan irregularity in Baghdad/Iraq to obtain the optimal behavior
  166. The effect of urban environment on large-scale path loss model’s main parameters for mmWave 5G mobile network in Iraq
  167. Formatting a questionnaire for the quality control of river bank roads
  168. Vibration suppression of smart composite beam using model predictive controller
  169. Machine learning-based compressive strength estimation in nanomaterial-modified lightweight concrete
  170. In-depth analysis of critical factors affecting Iraqi construction projects performance
  171. Behavior of container berth structure under the influence of environmental and operational loads
  172. Energy absorption and impact response of ballistic resistance laminate
  173. Effect of water-absorbent polymer balls in internal curing on punching shear behavior of bubble slabs
  174. Effect of surface roughness on interface shear strength parameters of sandy soils
  175. Evaluating the interaction for embedded H-steel section in normal concrete under monotonic and repeated loads
  176. Estimation of the settlement of pile head using ANN and multivariate linear regression based on the results of load transfer method
  177. Enhancing communication: Deep learning for Arabic sign language translation
  178. A review of recent studies of both heat pipe and evaporative cooling in passive heat recovery
  179. Effect of nano-silica on the mechanical properties of LWC
  180. An experimental study of some mechanical properties and absorption for polymer-modified cement mortar modified with superplasticizer
  181. Digital beamforming enhancement with LSTM-based deep learning for millimeter wave transmission
  182. Developing an efficient planning process for heritage buildings maintenance in Iraq
  183. Design and optimization of two-stage controller for three-phase multi-converter/multi-machine electric vehicle
  184. Evaluation of microstructure and mechanical properties of Al1050/Al2O3/Gr composite processed by forming operation ECAP
  185. Calculations of mass stopping power and range of protons in organic compounds (CH3OH, CH2O, and CO2) at energy range of 0.01–1,000 MeV
  186. Investigation of in vitro behavior of composite coating hydroxyapatite-nano silver on 316L stainless steel substrate by electrophoretic technic for biomedical tools
  187. A review: Enhancing tribological properties of journal bearings composite materials
  188. Improvements in the randomness and security of digital currency using the photon sponge hash function through Maiorana–McFarland S-box replacement
  189. Design a new scheme for image security using a deep learning technique of hierarchical parameters
  190. Special Issue: ICES 2023
  191. Comparative geotechnical analysis for ultimate bearing capacity of precast concrete piles using cone resistance measurements
  192. Visualizing sustainable rainwater harvesting: A case study of Karbala Province
  193. Geogrid reinforcement for improving bearing capacity and stability of square foundations
  194. Evaluation of the effluent concentrations of Karbala wastewater treatment plant using reliability analysis
  195. Adsorbent made with inexpensive, local resources
  196. Effect of drain pipes on seepage and slope stability through a zoned earth dam
  197. Sediment accumulation in an 8 inch sewer pipe for a sample of various particles obtained from the streets of Karbala city, Iraq
  198. Special Issue: IETAS 2024 - Part I
  199. Analyzing the impact of transfer learning on explanation accuracy in deep learning-based ECG recognition systems
  200. Effect of scale factor on the dynamic response of frame foundations
  201. Improving multi-object detection and tracking with deep learning, DeepSORT, and frame cancellation techniques
  202. The impact of using prestressed CFRP bars on the development of flexural strength
  203. Assessment of surface hardness and impact strength of denture base resins reinforced with silver–titanium dioxide and silver–zirconium dioxide nanoparticles: In vitro study
  204. A data augmentation approach to enhance breast cancer detection using generative adversarial and artificial neural networks
  205. Modification of the 5D Lorenz chaotic map with fuzzy numbers for video encryption in cloud computing
  206. Special Issue: 51st KKBN - Part I
  207. Evaluation of static bending caused damage of glass-fiber composite structure using terahertz inspection
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