Home Microstructure and chloride transport of aeolian sand concrete under long-term natural immersion
Article Open Access

Microstructure and chloride transport of aeolian sand concrete under long-term natural immersion

  • Wei Dong , AnQi Sun EMAIL logo and Menghu Zhou
Published/Copyright: March 12, 2024
Download Article (PDF)
Become an author with De Gruyter Brill
Submit Manuscript Author Information
Science and Engineering of Composite Materials
From the journal Science and Engineering of Composite Materials Volume 31 Issue 1

Abstract

River sand was consumed in large quantities, and alternatives to river sand were urgently needed. There are a large number of natural resources of aeolian sand in western China. Aeolian sand was prepared into aeolian sand concrete (ASC). It can greatly reduce the consumption of river sand and inhibit the process of desertification to protect the environment. ASC is a new type of concrete material prepared by using aeolian sand as fine aggregate. To clarify the chloride ion transport behaviour in the ASC under long-term natural immersion, the aeolian sand was 100% substituted for the river sand to prepare the full ASC with three water–binder ratios. The ASC was naturally immersed in 3 and 6% NaCl solutions for a long time, and nuclear magnetic resonance and microscopic scanning electron microscopy techniques were used. The change rule of chloride ion content at different depths of the ASC was studied, and its microstructure characteristics under different erosion times were analysed. The results showed that the free chloride ion concentration at different depths of the ASC increased with increasing water–binder ratio, immersion time, and chloride concentration. After soaking in the salt solution, the hydration products in the ASC reacted with chloride ions to form Friedel salt, which filled the internal pores and microcracks of the ASC, improved its interface transition zone structure, and increased the compactness of the test piece. The porosity of the three groups of ASC with different water–binder ratios decreased by 0.95, 1.03, and 1.15% after soaking in 6% salt solution for 12 m. To study the diffusion law of chloride ions in ASC, combined with influencing factors such as temperature, humidity, D value, deterioration effect and chloride ion combination, Fick’s second law was modified, and a chloride ion diffusion model of ASC with high accuracy was established, with a fitting correlation number above 0.93, which provided a reference for the research and application of ASC in saline areas.

Keywords: concrete; aeolian sand; water–binder ratio; chloride ion; chloride diffusion mode

1 Introduction

China is one of the countries with the most serious desertification, with desertification land accounting for 20% of its land resources in 2020 [1]. The research and application of aeolian sand concrete (ASC) can absorb a large amount of desert sand resources and alleviate the shortage of river sand resources [2]. With the implementation of China’s “Belt and Road” strategy, a large number of concrete structures need to serve in complex environments, such as western salt lakes and coastal environments, where a large number of chloride ions accelerate the deterioration of concrete [3]. Therefore, it is of great significance to study the chloride ion transport of ASC under long-term natural immersion.

To clarify the transport behaviour of chloride ions in concrete, Dong et al. [4,5,6] studied the transport of chloride ions in ASC and found that chloride salt erosion caused a variety of crystals inside the concrete, which filled the internal cementation hole and blocked the diffusion of chloride ions. Chloride ion diffusion is affected by many factors, such as aggregates and pores [7,8]. Cao et al. [9,10,11] improved the performance of the interfacial region by adding carbon fibre. The results showed that the addition of carbon fibre can significantly improve the mechanical properties of the material, which leads to better durability and working performance. Gao et al. [12,13] studied the chloride ion transport behaviour in the interface area of recycled concrete and found that modified recycled coarse aggregate could make the interface transition zone (ITZ) structure more compact, which was beneficial to resist chloride ion erosion. However, when the ITZ structure of old aggregate and old mortar was dense, chloride ions could penetrate into the ITZ structure of recycled aggregate and new mortar and then enter the mortar matrix through pores and cracks, weakening the corrosion resistance of concrete. Tian et al. [14,15,16,17] proved that ITZ increased the diffusion rate of chloride ions by establishing a microscopic model of chloride ion diffusion in saturated concrete. Qiao et al. [18,19] simulated the transport of chloride ions in saturated and unsaturated concrete through numerical simulation. The research showed that the diffusion of chloride ions was dominant when the concrete was saturated, and convection was dominant in the unsaturated state. At present, most chloride ion diffusion models are established through Fick’s law, and there are various chloride ion transport models and simulation methods [20,21,22,23]. However, there are many factors affecting chloride ion diffusion, and the existing models have difficulty accurately reflecting the chloride ion transport law. Due to the complexity of concrete structures, simulation analysis is only an auxiliary research tool and cannot completely replace tests.

In summary, there are few studies on the chloride ion transport behaviour of ASC under long-term natural immersion, and most of the studies are numerical simulations. Based on this, this study uses chemical titration, scanning electron microscopy (SEM), and nuclear magnetic resonance (NMR) to analyse the transport law of chloride ions in ASC under long-term natural immersion in different concentrations of NaCl solution and establish a more accurate chloride ion diffusion model, which provides a reference for the research and engineering application of chloride ion transport law in ASC.

2 Experimental design and method

2.1 Materials

The cement was P•O 42.5 Portland cement (Inner Mongolia, China) was used. The Grade-II fly ash was used. The coarse aggregate has a size of between 5 and 25 mm. The aeolian sand was collected from the surface of the Kubuqi Desert in north central China, with a particle size range of 0.075–0.25 mm, and the physical indicators are shown in Table 1. The tap water and admixture polycarboxylate superplasticiser were used.

Table 1

Main physical indexes of fine aggregate

Type Apparent density (kg m−3) Bulk density (kg m−3) Moisture content (%) Mud content (%) Chloride ion content (%) Fineness modulus
Aeolian sand 2,650 1,660 0.25 0.32 0.02 0.8

Note: Percentage in the table is the mass fraction.

2.2 Concrete mix proportion and preparation

In accordance with Chinese code (Specification for mix proportion design of ordinary concrete JGJ 55-2016), the aeolian sand was 100% replaced by river sand to prepare 100 mm × 100 mm × 100 mm cube specimens. The design water–binder ratios were 0.4, 0.45, and 0.55. Table 2 shows the mix ratio of ASC.

Table 2

Mix proportion of aeolian sand concrete

Specimen Water–binder ratio Mix proportion (kg m−3)
Cement Water Aeolian sand Stone Fly ash Water reducer
ASC-1 0.4 425 188 662 1,080 45 4.70
ASC-2 0.45 390 195 675 1,097 43 4.33
ASC-3 0.55 330 200 697 1,138 35 3.65

2.3 Test method

The ASC test block is sealed with epoxy resin on five sides, leaving one side as the erosion surface. The oven temperature was adjusted to 105°C and dried to constant weight. The test piece was placed in different concentrations of salt solution (3 and 6% NaCl) so that the liquid level was 1–2 cm higher than the test piece. After soaking 0, 1, 3, 5, 8, and 12 m, the powder was obtained by layered drilling (powder depth 0–5, 5–10, 10–15, 15–20, 20–25, 25–30, and 30–35 mm). The soaking solution was replaced once a month. The content of free chloride ions in the powder was titrated by chemical titration according to Chinese code (technical specification for concrete test and inspection of waterway engineering JTS/T 236-2019), and the relevant data were recorded.

The microstructure of the samples soaked in 3% NaCl solution for 12 m was observed by SEM. To improve the conductivity of the sample and make the observation clear, the sample was glued to the tray with conductive tape before the observation and then gold-plated in the vacuum diffraction gold spray instrument. The micromorphology of the sample was observed at an accuracy of 20 μm.

The pore structure of the samples was analysed by an NMR analyser. The specimens without soaking treatment and 3 and 6% NaCl solution soaking for 12 m were drilled and sampled, and the sampling site was the centre of the specimen. The sample was made into a Ф48 mm × H50 mm cylinder and placed in a 0.1 MPa vacuum saturation device for vacuum saturation. An NMR test was performed after the sample reached saturation.

3 Results and discussion

3.1 Quality loss rate

Figure 1 shows the relationship between the mass loss rate and time of ASC after long-term immersion. It can be seen from Figure 1 that when the concentration of the erosion solution is 3%, the mass loss rate increases rapidly and tends to be stable in the eighth month. When the concentration of the erosion solution is 6%, it tends to be stable after five months of long-term immersion, and the growth rate of the mass loss rate is extremely slow in 5–12 months. In the 12th month, the final mass loss rates of ASC-1, ASC-2, and ASC-3 in the 3% NaCl erosion solution are −0.55, −0.58, and −0.62%, respectively, and the final mass loss rates in the 6% NaCl erosion solution are −0.67, −0.7, and −0.75%, respectively. When the concentration of NaCl solution increases from 3 to 6%, the mass loss rates of ASC-1, ASC-2, and ASC-3 decrease further, and the reduction rates are −0.12, −0.12, and −0.13%, respectively.

Figure 1 Quality loss rate. (a) 3% NaCl and (b) 6% NaCl.
Figure 1

Quality loss rate. (a) 3% NaCl and (b) 6% NaCl.

The phenomenon of negative growth in the mass loss rate caused by concrete immersion in corrosive solution is that in the early stage of erosion, the hydration of concrete has just been completed, the internal pores are dry, and the capillary absorption capacity is strong. When concrete is placed in the corrosive solution, the solution enters the concrete through capillary absorption, which increases the quality of the concrete. The greater the water–binder ratio of the concrete is, the more internal capillary pores there are, and the stronger the capillary absorption capacity. When the water–binder ratio is the same and the external solution concentration is different, the greater the concentration difference between the inside and outside of the concrete, the faster the NaCl in the external erosion solution enters the concrete through capillary absorption in the state of Na+ and Cl−. In the 3 and 6% NaCl corrosion solutions, the mass loss rate of ASC produces inflection points at 8 and 5 m, respectively, and then, the loss rate tends to be balanced because Na+ and Cl− had physical-chemical reactions with Ca(OH)2 in the concrete, which is adsorbed at the capillary pore diameter or generates tiny particles to block the pores [24,25], preventing the external solution from entering the concrete.

3.2 Compressive strength

Figure 2 shows the compressive strength variation of ASC under long-term immersion. The compressive strength of ASC with a high water–binder ratio decreases. This is due to the poor gradation of aeolian sand, which cannot improve the gradual gap, increase the specific surface area of the aggregate, and reduce the encapsulation of the aggregate by the mortar matrix. The larger the water–binder ratio, the dosage of cement gradually decreases, and the cementitious material cannot fully encapsulate the sand aggregate, so that the bonding force between the mortar and the aggregate decreases, and a large number of tiny pores are formed inside the concrete. The structure of the concrete ITZ becomes weaker, resulting in a decrease in the compressive strength of the concrete.

Figure 2 Compressive strength. (a) 3% NaCl compressive strength and (b) 6% NaCl compressive strength.
Figure 2

Compressive strength. (a) 3% NaCl compressive strength and (b) 6% NaCl compressive strength.

Taking the ASC-1 group as an example, the compressive strength of 12 m immersed in 6% NaCl solution is 66.05 MPa, which is 3.75% higher than that of 3% NaCl solution 63.66 MPa. The compressive strength of ASC specimens immersed in 6% NaCl solution is better than that of ASC specimens immersed in 3% NaCl solution. This is because when concrete is immersed in a high-concentration solution, chloride ions enter the concrete specimen. When the ion concentration reaches a certain value, the ions will adsorb in the channel, react with the hydration products, fill the capillary channel, and make the ITZ structure of the concrete more compact. Macroscopically, the compressive strength of concrete increases [26].

3.3 Distribution of free chloride ion content

Figure 3 shows the distribution of free chloride ion content in ASC-1, ASC-2, and ASC-3 after soaking in 3 and 6% NaCl solutions at different times. Figure 3 shows that with increasing water–binder ratio, salt solution concentration, and soaking time, the amount and depth of chloride ion intrusion increased. The larger the water–binder ratio is, the worse the compactness of the concrete is, the better the connectivity between the pores is, and the chloride ion is easier to transport into the concrete. Therefore, the free chloride ion content in concrete with a large water–binder ratio is higher. The higher the concentration of salt solution is, the greater the concentration difference during immersion, which promotes the erosion of chloride ions into the interior and increases the free chloride ion content in the specimen.

Figure 3 Distribution of chloride ion content in aeolian sand concrete after immersion. (a) ASC-1 (3%), (b) ASC-2 (3%), (c) ASC-3 (3%), (d) ASC-1 (6%), (e) ASC-2 (6%), (f) ASC-3 (6%).
Figure 3

Distribution of chloride ion content in aeolian sand concrete after immersion. (a) ASC-1 (3%), (b) ASC-2 (3%), (c) ASC-3 (3%), (d) ASC-1 (6%), (e) ASC-2 (6%), (f) ASC-3 (6%).

To accurately analyse the transmission behaviour of free chloride ions in ASC with different water–binder ratios after soaking for 1, 3, 5, 8, and 12 m, the integral area of free chloride ion content is used to quantify the free chloride ion content at different depths in ASC, as shown in Figure 4.

Figure 4 Integral area diagram of chloride ion content. (a) 3% NaCl, and (b) 6% NaCl.
Figure 4

Integral area diagram of chloride ion content. (a) 3% NaCl, and (b) 6% NaCl.

Combined with Figures 3 and 4, it can be seen that (1) with increasing soaking time, the integral area of the free chloride ion content in the ASC increases. Taking ASC-3 immersed in 3% NaCl solution as an example, the free chloride ion content of the specimens with immersion times of 12, 8, 5, and 3 m at 2.5 mm increased by 70.15, 40.71, 29.44, and 18.37%, respectively, compared with that at 1 m, and the integral area of the free chloride ion content increased by 90.73, 45.42, 29.51, and 15.83%, respectively. (2) When the salt solution concentration and soaking time are the same, the larger the water–binder ratio of the ASC is, the larger the free chloride ion content and the integral area, and the easier the chloride ion migrates into the ASC. For example, after ASC-3 is immersed in a 3% NaCl solution for 12 m, the free chloride ion content at 2.5 mm increases by 9.54 and 4.49% compared with ASC-1 and ASC-2, and the integral area of the free chloride ion content increases by 16.69 and 12.31%. (3) When the water–binder ratio and soaking time were the same, with increasing salt solution concentration, the free chloride ion content at different depths of ASC in each group showed an increasing trend. For example, after the ASC-1 group is immersed in a salt solution for 12 m, the free chloride ion concentration at 2.5 mm in the 6% NaCl group increases by 0.125% compared with that in the 3% NaCl group.

3.4 Microstructure analysis

3.4.1 SEM analysis

To analyse the microstructure change characteristics of ASC after long-term natural immersion in NaCl solution, the internal hydration products and ITZ structure of ASC-1 and ASC-3 specimens after immersion in 3% NaCl solution for 12 m were observed by SEM. Figures 5 and 6 show the microstructure of the ASC after soaking. Figures 5 and 6 show the microstructure of the ASC after soaking. It can be seen from Figure 5 that after long-term natural immersion in chloride salt, the structure of the ITZ is improved, and the compactness is good. It can be seen from Figure 6 that after long-term natural immersion in chloride salt, the structure of the ITZ is improved, and the compactness is good. There are no cracks at the junction of the aggregate and mortar matrix, but there are microcracks in the mortar matrix, with a small number and width, and no obvious holes are observed. This shows that the long-term natural immersion of NaCl solution has no obvious damage to the internal microstructure of ASC but has an enhancement effect on the ITZ structure. The reason is that the ITZ structure is the weak part of the ASC. The combination of aggregate and mortar matrix is prone to cracks, and the porosity of the nearby mortar matrix is high, which is the main channel for chloride ion transport. When the salt solution enters the interior of the ASC, it reacts with the hydration products to form Friedel salt [27,28], which fills the ITZ and microcracks, making the interior denser, reducing the porosity, and improving the structure.

Figure 5 Micromorphology after immersion in 3% salt solution for 12 m. (a) ASC-1. (b) ASC-3.
Figure 5

Micromorphology after immersion in 3% salt solution for 12 m. (a) ASC-1. (b) ASC-3.

Figure 6 Morphology of hydration products in aeolian sand concrete after immersion in 3% NaCl solution. (a) ASC-1. (b) ASC-3.
Figure 6

Morphology of hydration products in aeolian sand concrete after immersion in 3% NaCl solution. (a) ASC-1. (b) ASC-3.

From Figure 6, it can be seen that after soaking for 12 m, most of the hydration products are lamellar, and some products are “nested” with each other, showing good integrity. At the same time, Friedel salts can be observed on the surface of the hydration products, some of which are distributed in a “needle-like” or “flocculent” shape, and some form layered structures. In addition, a small amount of lamellar Ca(OH)2 and hexahedral salt crystals can be observed in the hydration products.

3.4.2 NMR analysis

Figures 7 and 8 show the NMR T2 spectrum and T2 spectrum area of ASC after soaking in 3 and 6% NaCl solutions for 12 m. According to Figure 7, the T2 spectrum of ASC shows 3–4 peaks, and the first peak accounts for the largest proportion. With increasing NaCl solution concentration, the T2 spectrum moves to the left, and the total area and the first peak signal amplitude decay. In Figure 8, the total T2 spectrum area of the ASC-1, ASC-2, and ASC-3 groups decreases from 5286.691, 7491.198, and 8321.922 to 1826.208, 2541.198, and 3618.209, respectively. The total T2 spectrum area decreases by 9.54% when ASC-3 is immersed in a 3% salt solution for 12 m and decreases by 51.98% when the solution concentration increases from 3 to 6%.

Figure 7 T2 spectrum of aeolian sand concrete before and after immersion in NaCl solution. (a) ASC-1. (b) ASC-2. (c) ASC-3.
Figure 7

T2 spectrum of aeolian sand concrete before and after immersion in NaCl solution. (a) ASC-1. (b) ASC-2. (c) ASC-3.

Figure 8 Peak area of T2 spectrum of aeolian sand concrete before and after immersion in NaCl solution. (a) 0% NaCl. (b) 3% NaCl. (c) 6% NaCl.
Figure 8

Peak area of T2 spectrum of aeolian sand concrete before and after immersion in NaCl solution. (a) 0% NaCl. (b) 3% NaCl. (c) 6% NaCl.

The reason is that after chloride ions enter the ASC, physical adsorption and chemical bonding occur with the cement hydration products, filling the internal pores and reducing the pore size and the number of pores, resulting in a left shift of the T2 spectrum and a decrease in the first peak area. The increasing amount of chloride ion intrusion causes salt crystallisation in the ASC, and the reaction of chloride ions with hydration products reduces the porosity, resulting in a decrease in the total area of the T2 spectrum. With increasing NaCl solution concentration, the concentration difference between the inside and outside of the specimen becomes larger, the transmission of chloride ions to the inside of the specimen increases, and the porosity decreases more. The decrease in porosity increases the tortuosity of pores, resulting in an increase in the viscous resistance of Cl- and water during transport, a decrease in transport rate and depth, and a slower increase in chloride ion content in the later period.

According to Bout’s classification method, the pore structure is divided into four categories: gel pores (r < 10 nm), transition pores (10 nm < r < 100 nm), capillary pores (100 nm < r < 1,000 nm), and macropores (r > 1,000 nm). Figure 9 shows the proportion of pore size classification of ASC after soaking in 3% NaCl and 6% NaCl solutions for 12 m. The comparative analysis shows that with the increase in the concentration of chloride solution, the number of gel pores of ASC increased significantly after soaking. ASC-1 increased from 68 to 90%, an increase of 22%, and ASC-3 increased from 33 to 86%, an increase of 53%. The number of transition holes decreased significantly, ASC-1 decreased from 24 to 7%, decreasing by 17%, and ASC-3 decreased from 51 to 10%, decreasing by 41%. The number of pores and macropores decreased slightly. This is because with increasing capillary absorption time, the amount of chloride ion intrusion increases, the internal hydration reaction continues, and the physical and chemical combination of chloride ions and hydration products produces Friedel salt, which increases the interior density and the number of holes.

Figure 9 Percentage of pore size distribution under different salt concentration immersion. (a) Cementation porosity. (b) Transitional porosity. (c) Capillary porosity. (d) Macropore porosity.
Figure 9

Percentage of pore size distribution under different salt concentration immersion. (a) Cementation porosity. (b) Transitional porosity. (c) Capillary porosity. (d) Macropore porosity.

The changes in porosity and saturation of ASC after soaking in NaCl solution are shown in Figure 10. Figure 10 shows that with increasing soaking time and salt solution concentration, the free fluid saturation and porosity of concrete decrease, and the bound fluid saturation increases. After soaking in 6% NaCl solution for 12 m, the free fluid saturation of the ASC-1, ASC-2, and ASC-3 groups decreases by 15, 17, and 19%, respectively, and the porosity decreases by 0.95, 1.03, and 1.15%, respectively.

Figure 10 Change of concrete saturation and porosity before and after immersion in NaCl solution. (a) Not stocked, (b) 3% NaCl, and (c) 6% NaCl.
Figure 10

Change of concrete saturation and porosity before and after immersion in NaCl solution. (a) Not stocked, (b) 3% NaCl, and (c) 6% NaCl.

With increasing soaking time, the amount of water and chloride ion intrusion increases, and the internal hydration products are further hydrated. Coupled with the reaction of chloride ions and hydration products, the reaction products fill the interior of concrete, improve the internal compactness, reduce the porosity, and deteriorate the connectivity between pore structures. With increasing NaCl solution concentration, the concentration difference between the inside and outside of the pores increases the amount of chloride ions and water intrusion, the connectivity of the internal pore structure worsens, the number of closed pores increases, the number of open pores decreases, and the porosity and free fluid saturation decrease.

3.5 Chloride ion diffusion model of aeolian sand concrete

The diffusion of chloride ions in concrete generally satisfies Fick’s second law. The use of Fick’s second law requires three points: (1) concrete is regarded as a semi-infinite homogeneous medium; (2) Cl− does not react with porous media in the diffusion process; and (3) the diffusion coefficient D is a fixed value. In the actual test, Cl− will react with the gel material inside the concrete, and the reaction product will hinder the diffusion of chloride ions and reduce the diffusion rate. In addition, due to the influence of multiple factors, such as temperature, humidity, soaking period, and physical damage, the chloride ion diffusion coefficient D is not a fixed value.

In summary, to establish a more accurate chloride ion diffusion model of ASC, the chloride ion diffusion model is modified based on Fick’s second law. Chloride ion diffusion is sensitive to temperature. The higher the temperature is, the faster the chloride ion diffusion rate [29]. The effect of temperature on the chloride diffusion coefficient is shown in the following equation:

(1) D ( T ) = D ref ⋅ f 1 ( T ) = D ref ⋅ exp U R ⋅ 1 T ref − 1 T ,

where T ref and D ref are the absolute temperature of curing 28 days and chloride diffusion coefficient at T ref; T, D(T), and f 1(t) are absolute temperature when calculating, chloride diffusion coefficient at temperature T, and temperature influence coefficient, respectively; and U is activation energy of diffusion process, When the ordinary Portland cement water–binder ratio is 0.4, 41,800 (J/mol) is taken, and 44,600 (J/mol) is taken when the water–binder ratio is 0.5; R is gas constant (8.314 J/mol K).

The water content in concrete is mainly affected by saturation, which is usually characterised by relative humidity. The effect of relative humidity on chloride ion diffusion in concrete is shown in the following equation [30]:

(2) D ( H ) = D ( H c ) ⋅ f 2 ( H ) = D ( H c ) ⋅ 1 + ( 1 − H ) 4 ( 1 − H c ) 4 − 1 ,

where H, f 2(H), and D(H) are the relative humidity, humidity influence coefficient, and chloride diffusion coefficient at relative humidity, respectively; H c and D(H c) are the critical relative humidity, generally 75%, and the chloride diffusion coefficient at critical relative humidity H c.

The functional relationship between the chloride ion diffusion coefficient D and age is shown in the following equation [31]:

(3) D ( t ) = D ref ⋅ f 3 ( t ) = D ref ⋅ t ref t m ,

where f 3(t) and t are the age influence coefficient and time, respectively; m is the attenuation coefficient; t ref, D ref, and D(t) are the reference time, chloride diffusion coefficient when the reference time is t ref, and chloride diffusion coefficient at time t, respectively.

The effect of damage on the chloride diffusion coefficient is shown in the following equation [32]:

(4) D = K ⋅ D ref ,

where K and D ref are the degradation index and D of defect-free concrete, respectively.

When the salt concentration gradient changes, the bound chloride ion concentration remains unchanged, so Fick’s second law can be expressed as:

(5) D = D ref ⋅ f 4 = D ref ⋅ 1 + 1 ∂ C b ∂ C f ,

where C b , C f , f 4 , and D ref are the combined chloride ion concentration, free chloride concentration, chloride binding coefficient and initial chloride diffusion coefficient, respectively.

Taking into account the impact of the five factors mentioned above on the diffusion coefficient of chloride ions, it can be expressed as

(6) D = D ref ⋅ f 1 ( T ) f 2 ( H ) f 3 ( t ) K f 4 .

By Fick’s second law, we consider the initial condition: C(x,0) = C0; when the boundary conditions are C(0,t) = C s, C(∞,t) = C 0, the following equation can be obtained by solving:

(7) C = C 0 + ( C s − C 0 ) 1 − erf x 2 D t ,

where C s, C 0, and erf(z) are the surface chloride ion concentration, initial chloride ion concentration, and Gauss error function, respectively.

D is obtained by fitting, which means the value of concrete exposed to chloride solution [33]. It is mainly calculated by the age of exposure to the chloride ion erosion environment that is the value of the reference time tref in equation (3):

(8) D = ∫ 0 t D ( t ) d t t .

Bring equation (3) into equation (8):

(9) D = ∫ 0 t D ref t ref t m d t t = D ref t ref m 1 − m ⋅ t 1 − m t = D ref 1 − m ⋅ t ref t m ,

where t is time and D ref is D when t = t ref.

Substituting equation (9) into equation (7), a chloride ion diffusion model considering time dependence can be obtained, that is:

(10) C = C 0 + ( C s − C 0 ) 1 − erf x 2 D ref t ref m 1 − m ⋅ t 1 − m .

D ref in equation (10) is replaced by D in equation (6), and influencing factors such as temperature, humidity, age, deterioration effect, and chloride binding effect are considered. The chloride ion diffusion model of ASC can be obtained:

(11) C f = C 0 + ( C s − C 0 ) × 1 − erf x 2 K D 0 t 0 m 1 + ( 1 − H ) 4 ( 1 − H c ) 4 − 1 ⋅ exp U R 1 T 0 − 1 T ( 1 + k ) ( 1 − m ) t 1 − m .

In the engineering application of the chloride ion diffusion model, it is necessary to give the values of the main parameters in the model, including m, C s, K, and k of the chloride ion diffusion coefficient. At present, the deterioration coefficient is used to evaluate the influence of concrete deterioration on chloride ion intrusion in practical engineering. The test environment is long-term natural immersion of chloride salt, which is close to the actual environment, so the deterioration coefficient K = 1; according to the Japanese Harbour Research Institute [34], k = 0.2302.

The value of m mainly depends on the composition of the concrete. Through Fick’s second law fitting, the chloride ion diffusion coefficient of ASC with different water–binder ratios under different chloride salt concentrations and long-term natural immersion is obtained, as shown in Table 3.

Table 3

Chloride ion diffusion coefficient of aeolian sand concrete

NaCl concentration ASC group Soaking time
1 m 3 m 5 m 8 m 12 m
3% NaCl ASC-1 76.750 22.880 12.710 9.125 4.063
ASC-2 82.450 26.880 13.790 9.424 5.564
ASC-3 94.530 27.090 13.970 9.567 5.600
6% NaCl ASC-1 101.400 28.780 14.450 9.402 6.743
ASC-2 109.100 32.130 15.760 9.555 6.758
ASC-3 118.000 32.240 16.760 9.847 8.005

Note: The unit in the table is (m2/s × 10−12).

According to formula (9), the corresponding m value can be obtained, as shown in Table 4.

Table 4

Attenuation coefficient m value

NaCl concentration 3% NaCl 6% NaCl
ASC group ASC-1 ASC-2 ASC-3 ASC-1 ASC-2 ASC-3
m 0.1658 0.699 0.746 0.749 0.758 0.782

In the long-term natural immersion process of chloride salt, the surface chloride ion concentration of the concrete structure is not constant but a process from low to high and gradually saturates. C s and t show simple linear, complex logarithmic, exponential, and power function relationships. According to the experimental data fitting, the C s = at b power function fitting effect is better and more in line with the actual situation, and the fitting results are shown in Table 5.

Table 5

Power function fitting between surface chloride concentration and time

ASC group 3% NaCl 6% NaCl
a b R 2 a b R 2
ASC-1 0.141 0.304 0.968 0.118 0.356 0.984
ASC-2 0.186 0.263 0.976 0.170 0.296 0.938
ASC-3 0.194 0.260 0.971 0.098 0.431 0.807

The free chloride ion concentration calculated by the modified chloride ion diffusion model of ASC is compared with the free chloride ion concentration test data of ASC after long-term natural immersion in 3 and 6% NaCl solutions for 12 m. The results are shown in Figure 11. It can be seen from Figure 11 that the difference between the theoretical value and the measured value of the free chloride ion concentration of ASC after soaking for 12 m is small, which proves that the established chloride ion diffusion model of ASC has high reliability (Table 6).

Figure 11 Fitting curve of the chloride diffusion model.
Figure 11

Fitting curve of the chloride diffusion model.

Table 6

Fitting correlation coefficient of the chloride ion diffusion model for aeolian sand concrete

ASC group 3% NaCl 6% NaCl
ASC-1 ASC-2 ASC-3 ASC-1 ASC-2 ASC-3
R 2 0.96 0.95 0.96 0.94 0.93 0.94

4 Main parameters and discussion of long-term soaking aeolian sand concrete

In practice, the Cl− diffusion will undergo a physical or chemical reaction with the gel material inside the concrete, which reduces the concentration of the chloride ions and the diffusion rate of the chloride ions. The chloride ion diffusion coefficient is not a fixed value and is affected by temperature, humidity, age, physical damage, and other factors. The main parameters of ASC after long-term immersion are shown in Table 7. It is shown that the diffusion coefficient of full ASC is similar to that of ordinary concrete. Full ASC with a low water-to-binder ratio has a strong resistance to chloride ion penetration, which is sufficient for practical engineering applications of ASC. Due to its similar impermeability to ordinary concrete, it is sufficient to ensure that the steel rods inside the concrete remain intact. In the future, ASC can be considered preliminary application in small buildings, such as warehouses and poultry houses.

Table 7

Main performance indexes of chloride ion resistance of aeolian sand concrete

ASC group NaCl concentration (%) 12 m mass loss rate (%) 12 m compressive strength (MPa) Chloride ion concentration integral area 12 m diffusion coefficient (m2/s × 10−12)
ASC-1 3 −0.67 66.1 10.065 4.063
6 −0.55 63.7 10.733 6.743
ASC-2 3 −0.7 57.3 10.458 5.564
6 −0.58 55.6 10.955 6.758
ASC-3 3 −0.75 49.9 11.745 5.600
6 −0.62 48.2 12.342 8.005

In this article, the ion diffusion behaviour of ASC is analysed in the form of long-term free diffusion of chloride ions. Compared with Zhou and Dong [35,36]. In the result of the test, it was found that in the freeze-thaw cycle test of the whole ASC, due to the large pores of the whole ASC, the pore evolution first changed from large pores to small pores, and then the pores expanded and cracked. The ability to resist freeze-thaw cycles is stronger than that of ordinary concrete. A comparison with Li et al. [37] found that the impermeability of full ASC was better, but the compressive strength of partially mixed specimens was higher than that of fully mixed specimens. On the whole, if the ASC is applied to practical engineering, the performance of the concrete is the best when the content of aeolian sand is 20%. At this time, the ASC has higher compressive strength and the diffusion coefficient is similar to that of ordinary concrete.

5 Conclusion and foresight

It is important to note that the total ASC has good impermeability, and its compressive strength is lower than that of ordinary concrete. Its good anti-permeability performance is due to the large pores in the pore structure of the whole ASC. After the solution is inhaled, a stable or semi-stable meniscus shape is formed at the interface between the solution and the air, which hinders further entry of the solution. However, its large pore size will reduce the compressive strength. Therefore, more research is needed to apply ASC to important buildings such as bridges and dams. Through experimental analysis, this study draws the following conclusions:

  1. The mass loss rates of ASC-1, ASC-2, and ASC-3 were −0.55, −0.58, and −0.62%, respectively, when they were immersed in 3% NaCl solution for 12 m and −0.67, −0.7, and −0.75%, respectively, when they were immersed in 6% NaCl solution. The greater the water–binder ratio of concrete, the greater the capillary pore diameter, the faster the chloride ion penetration, and the increase in corrosion solution concentration accelerated the chloride ion penetration rate, resulting in an increase in the mass loss rate.

  2. The compressive strength of ASC-1, ASC-2, and ASC-3 soaked in 6% NaCl solution at 12 is 3.75, 3.06, and 3.38% higher than that of 3% NaCl solution. The concentration of chloride ions in the outside world increased, the rate of entering the concrete was accelerated, and the hydration products reacted. The compressive strength of the ASC block soaked in 6% NaCl solution is better than that soaked in 3% NaCl solution.

  3. The larger the water–binder ratio, the easier the chloride ion was transmitted to the inside of the ASC, and the free chloride ion concentration and its integral area inside the specimen were relatively large. After the ASC-3 group was immersed in a 3% NaCl solution for 12 m, the free chloride ion content at 2.5 mm was 9.54 and 4.49% higher than that of the ASC-1 and ASC-2 groups, and the integral area of the free chloride ion content was increased by 16.69 and 12.31%. Under the same water–binder ratio and soaking time, the free chloride ion concentration at different depths of the ASC increased with increasing salt solution concentration.

  4. After soaking in NaCl solution for 12 m, the reaction products of chloride ions filled the internal pores and microcracks of the ASC and improved the ITZ structure of the concrete. With increasing salt solution concentration, the gel pores in ASC increased, and the transition pores and capillary pores decreased. Compared with the 3% salt solution, the gel pores increased by 53%, and the transition pores decreased by 41% in the ASC-3 group after soaking in the 6% salt solution for 12 m. The filling effect of reaction products worsens the connectivity between the pore structures of ASC, resulting in a decrease in free fluid saturation and an increase in bound fluid saturation. After soaking in 6% salt solution for 12 m, the free fluid saturation of the ASC-1, ASC-2, and ASC-3 groups decreased by 15, 17, and 19%, respectively.

  5. Considering the influence of temperature, humidity, age, deterioration effect, and chloride ion binding on the chloride ion diffusion coefficient of ASC, Fick’s second law was modified, and the modified chloride ion diffusion model of ASC was established.

Acknowledgements

The authors would like to thank Inner Mongolia University of Science and Technology for the assistance of field experiments.

  1. Funding information: We are very grateful to the National Natural Science Foundation of China (52268044, 52168033), the Natural Science Foundation of Inner Mongolia Autonomous Region (2021LHMS05019), the Basic Scientific Research Business Fund of Universities Directly under the Inner Mongolia Autonomous Region (2023QNJS161), the Open Fund Project of the Institute of Building Science of Inner Mongolia University of Science and Technology (JYSJJ-2021Q01), and the Kundulun District Science and Technology Program Project (YF2022012).

  2. Author contributions: WD: involved in methodology, conceptualisation, project management, and funding acquisition, AS: performed data collation, writing – review and editing, and MZ: methodology, writing – review and editing.

  3. Conflict of interest: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

  4. Data availability statement: The data used to support the findings of this study are available from the corresponding author upon reasonable request.

References

[1] Wang YH, Chu Q, Han Q. Filling effect of kubuqi aeolian sand on different classifications of river sand. J Build Mater. 2021;24(1):191–8.Search in Google Scholar

[2] Chao LI, Xin LI, Chao ZH, Huawei LI. Research progress on application of aeolian sand in concrete. J Mater Sci Eng. 2022;40(4):695–705.Search in Google Scholar

[3] Wang Q, Zhang G, Tong Y, Gu C. A numerical study on chloride diffusion in cracked concrete. Crystals. 2021;11(7):742.10.3390/cryst11070742Search in Google Scholar

[4] Dong W, Fu QW, Liu X, Wang D, Wang XS. Migration law of water and chloride ions in aeolian sand concrete. J Drain Irrig Mach Eng. 2022;40(9):908–14.Search in Google Scholar

[5] Xue HJ, Shen XD, Wang RY, Liu Q, Liu Z. Mechanism analysis of chloride-resistant erosion of aeolian sand concrete under wind-sand erosion and dry-wet circulation. Trans Chin Soc Agric Eng. 2017;33(18):118–26.Search in Google Scholar

[6] Xiong QX, Liu QF, Zhang XJ, Chen C. Chloride diffusion prediction in concrete through mathematical models based on time-dependent diffusion coefficient and surface chloride concentration. J Mater Civ Eng. 2022;34(11):04022309.10.1061/(ASCE)MT.1943-5533.0004429Search in Google Scholar

[7] Nukushina T, Takahashi Y, Ishida T. Numerical simulations of chloride transport in concrete considering connectivity of chloride migration channels in unsaturated pores. J Adv Concr Technol. 2021;19(7):847–63.10.3151/jact.19.847Search in Google Scholar

[8] Cai Y, Liu Q, Meng Z, Chen M, Li W, Šavija B. Influence of coarse aggregate settlement induced by vibration on long-term chloride transport in concrete: a numerical study. Mater Struct. 2022;55(9):235.10.1617/s11527-022-02038-zSearch in Google Scholar

[9] Cao D, Bouzolin D, Lu H, Griffith DT. Bending and shear improvements in 3D-printed core sandwich composites through modification of resin uptake in the skin/core interphase region. Compos Part B: Eng. 2023;264:110912.10.1016/j.compositesb.2023.110912Search in Google Scholar

[10] Cao D. Enhanced buckling strength of the thin-walled continuous carbon fiber–reinforced thermoplastic composite through dual coaxial nozzles material extrusion process. Int J Adv Manuf Technol. 2023;128(3–4):1305–15.10.1007/s00170-023-12014-8Search in Google Scholar

[11] Cao D. Strengthening the interphase of thermoplastic sandwich composites by interleaving carbon nanotube yarns. Mater Today Commun. 2023;36:106655.10.1016/j.mtcomm.2023.106655Search in Google Scholar

[12] Gao S, Guo J, Gong Y, Ban S, Liu A. Study on the penetration and diffusion of chloride ions in interface transition zone of recycled concrete prepared by modified recycled coarse aggregates. Case Stud Constr Mater. 2022;16:e01034.10.1016/j.cscm.2022.e01034Search in Google Scholar

[13] Xia J, Chen K, Hu S, Chen J, Wu R, Jin W. Experimental and numerical study on the microstructure and chloride ion transport behavior of concrete-to-concrete interface. Constr Build Mater. 2023;367:130317.10.1016/j.conbuildmat.2023.130317Search in Google Scholar

[14] Tian Y, Jin HD, Tian ZS, Jin XY, Yu W. 3D mesoscopic model for chloride transport in concrete. J Build Mater. 2020;23(2):286–91.Search in Google Scholar

[15] Chen XD, Yu AP, Liu GY, Huang D, Yu XF. Meso-numerical simulation of service life prediction for marine structures. J Build Mater. 2019;22(6):894–900.Search in Google Scholar

[16] Zhou SX, Han Z, Wei X, Wei YQ, Yu LH. Influence of aggregate contents and volume of interfacial transition zone on chloride ion diffusion properties of concrete. J Build Mater. 2018;21(3):351–7.Search in Google Scholar

[17] Ding Y, Yang TL, Liu H, Han Z, Zhou SX, Wang ZP, et al. Experimental study and simulation calculation of the chloride resistance of concrete under multiple factors. Appl Sci. 2021;11(12):5322.10.3390/app11125322Search in Google Scholar

[18] Qiao HX, Qiao GB, Lu CG. Simulation and velocity analysis of chloride ion transport in concrete. J Huazhong Univ Sci Technol (Nat Sci Ed). 2022;50(2):19–25.Search in Google Scholar

[19] Zhang Y, Giovnni LD, Mohammed A. Coupled multi-physics simulation of chloride diffusion in saturated and unsaturated concrete. Constr Build Mater. 2021;292:123394.10.1016/j.conbuildmat.2021.123394Search in Google Scholar

[20] Liu Z, Wang Y, Wang J, Liu C, Jiang J, Li H. Experiment and simulation of chloride ion transport and binding in concrete under the coupling of diffusion and convection. J Build Eng. 2022;45:103610.10.1016/j.jobe.2021.103610Search in Google Scholar

[21] Liu JL, Wang Y. Predicting the chloride diffusion in concrete incorporating fly ash by a multi-scale model. J Clean Prod. 2022;330:129767.10.1016/j.jclepro.2021.129767Search in Google Scholar

[22] Zhang JH, Liu YH, Shi ZM. Diffusion property of chloride in cracked concrete. J Build Mater. 2018;21(2):299–303.Search in Google Scholar

[23] Ma C, Zhang F, Liu H, Wang H, Hu J. Experimental study of the effects of graphene nanoplatelets on microstructure and compressive properties of concrete under chloride ion corrosion. Constr Build Mater. 2022;360:129564.10.1016/j.conbuildmat.2022.129564Search in Google Scholar

[24] Yu K, Liu Y, Jia M, Wang C, Yang Y. Thermal energy storage cement mortar containing encapsulated hydrated salt/fly ash cenosphere phase change material: Thermo-mechanical properties and energy saving analysis. J Energy Storage. 2022;51:104388.10.1016/j.est.2022.104388Search in Google Scholar

[25] Yu K, Jia M, Yang Y, Liu Y. A clean strategy of concrete curing in cold climate: Solar thermal energy storage based on phase change material. Appl Energy. 2023;331:120375.10.1016/j.apenergy.2022.120375Search in Google Scholar

[26] Hyun KS, Ha YK, Sang HL. Convolutional neural network-based regression for predicting the chloride ion diffusion coefficient of concrete. Comput Mater Continua. 2022;3(70):5059–71.10.32604/cmc.2022.017262Search in Google Scholar

[27] Yang L, Zhang YS, Andrade C, Zhang CX. Study on the correlation between chloride ion transportation and pH distribution in unsaturated mortar. Mater Rep. 2021;35(18):18064–8.Search in Google Scholar

[28] Lian S, Ruan S, Zhan S, Unluer C, Meng T, Qian K. Unlocking the role of pores in chloride permeability of recycled concrete: A multiscale and a statistical investigation. Cem Concr Compos. 2022;125:104320.10.1016/j.cemconcomp.2021.104320Search in Google Scholar

[29] Chen Q, Gong W, Miao JJ. Corrosion extents of steel bar in copper slag concrete after exposure to high temperature under chloride attack. Acta Materiae Compositae Sin. 2022;39(6):2875–84.Search in Google Scholar

[30] Bazant ZP, Najiar LJ. Nonlinear water diffusion in nonsaturated concrete. Mater & Struct. 1972;5(25):3–20.10.1007/BF02479073Search in Google Scholar

[31] Thomas M, Bamforth PB. Modelling chloride diffusion in concrete effect of fly ash and slag. Cem Concr Res. 1999;29(4):487–95.10.1016/S0008-8846(98)00192-6Search in Google Scholar

[32] Yu HF, Sun W, Ma HY, Yan LH. Diffusion equations of chloride ion in concrete under the combined action of durability factors. J Build Mater. 2002;3:240–7.Search in Google Scholar

[33] Tang L, Gulikers J. On the mathematics of time-dependent apparent chloride diffusion coefficient in concrete. Cem Concr Res. 2007;37(4):589–95.10.1016/j.cemconres.2007.01.006Search in Google Scholar

[34] Mohammed UT, Hamada H. Relationship between free chloride and total chloride contents in concrete. Cem Concr Res. 2003;33(9):1487–90.10.1016/S0008-8846(03)00065-6Search in Google Scholar

[35] Zhou M, Dong W. Grey relativity correlations between the pore structures and compressive strength of aeolian sand concrete undergoing carbonation and freeze-thaw cycles. J Build Eng. 2023;77:107515.10.1016/j.jobe.2023.107515Search in Google Scholar

[36] Zhou M, Dong W. Grey correlation analysis of macro-and micro-scale properties of aeolian sand concrete under the salt freezing effect. Structures. Vol. 58, Elsevier; 2023. p. 105551.10.1016/j.istruc.2023.105551Search in Google Scholar

[37] Li Y, Zhang H, Chen S, Wang H, Liu G. Multi-scale study on the durability degradation mechanism of aeolian sand concrete under freeze–thaw conditions. Constr Build Mater. 2022;340:127433.10.1016/j.conbuildmat.2022.127433Search in Google Scholar
Received: 2023-07-25
Revised: 2024-01-05
Accepted: 2024-02-02
Published Online: 2024-03-12

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

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

Articles in the same Issue

  1. Regular Articles
  2. Research on damage evolution mechanisms under compressive and tensile tests of plain weave SiCf/SiC composites using in situ X-ray CT
  3. Structural optimization of trays in bolt support systems
  4. Continuum percolation of the realistic nonuniform ITZs in 3D polyphase concrete systems involving the aggregate shape and size differentiation
  5. Multiscale water diffusivity prediction of plain woven composites considering void defects
  6. The application of epoxy resin polymers by laser induction technologies
  7. Analysis of water absorption on the efficiency of bonded composite repair of aluminum alloy panels
  8. Experimental research on bonding mechanical performance of the interface between cementitious layers
  9. A study on the effect of microspheres on the freeze–thaw resistance of EPS concrete
  10. Influence of Ti2SnC content on arc erosion resistance in Ag–Ti2SnC composites
  11. Cement-based composites with ZIF-8@TiO2-coated activated carbon fiber for efficient removal of formaldehyde
  12. Microstructure and chloride transport of aeolian sand concrete under long-term natural immersion
  13. Simulation study on basic road performance and modification mechanism of red mud modified asphalt mixture
  14. Extraction and characterization of nano-silica particles to enhance mechanical properties of general-purpose unsaturated polyester resin
  15. Roles of corn starch and gellan gum in changing of unconfined compressive strength of Shanghai alluvial clay
  16. A review on innovative approaches to expansive soil stabilization: Focussing on EPS beads, sand, and jute
  17. Experimental investigation of the performances of thick CFRP, GFRP, and KFRP composite plates under ballistic impact
  18. Preparation and characterization of titanium gypsum artificial aggregate
  19. Characteristics of bulletproof plate made from silkworm cocoon waste: Hybrid silkworm cocoon waste-reinforced epoxy/UHMWPE composite
  20. Experimental research on influence of curing environment on mechanical properties of coal gangue cementation
  21. Multi-objective optimization of machining variables for wire-EDM of LM6/fly ash composite materials using grey relational analysis
  22. Synthesis and characterization of Ag@Ni co-axial nanocables and their fluorescent and catalytic properties
  23. Beneficial effect of 4% Ta addition on the corrosion mitigation of Ti–12% Zr alloy after different immersion times in 3.5% NaCl solutions
  24. Study on electrical conductive mechanism of mayenite derivative C12A7:C
  25. Fast prediction of concrete equivalent modulus based on the random aggregate model and image quadtree SBFEM
  26. Research on uniaxial compression performance and constitutive relationship of RBP-UHPC after high temperature
  27. Experimental analysis of frost resistance and failure models in engineered cementitious composites with the integration of Yellow River sand
  28. Influence of tin additions on the corrosion passivation of TiZrTa alloy in sodium chloride solutions
  29. Microstructure and finite element analysis of Mo2C-diamond/Cu composites by spark plasma sintering
  30. Low-velocity impact response optimization of the foam-cored sandwich panels with CFRP skins for electric aircraft fuselage skin application
  31. Research on the carbonation resistance and improvement technology of fully recycled aggregate concrete
  32. Study on the basic properties of iron tailings powder-desulfurization ash mine filling cementitious material
  33. Preparation and mechanical properties of the 2.5D carbon glass hybrid woven composite materials
  34. Improvement on interfacial properties of CuW and CuCr bimetallic materials with high-entropy alloy interlayers via infiltration method
  35. Investigation properties of ultra-high performance concrete incorporating pond ash
  36. Effects of binder paste-to-aggregate ratio and polypropylene fiber content on the performance of high-flowability steel fiber-reinforced concrete for slab/deck overlays
  37. Interfacial bonding characteristics of multi-walled carbon nanotube/ultralight foamed concrete
  38. Classification of damping properties of fabric-reinforced flat beam-like specimens by a degree of ondulation implying a mesomechanic kinematic
  39. Influence of mica paper surface modification on the water resistance of mica paper/organic silicone resin composites
  40. Impact of cooling methods on the corrosion behavior of AA6063 aluminum alloy in a chloride solution
  41. Wear mechanism analysis of internal chip removal drill for CFRP drilling
  42. Investigation on acoustic properties of metal hollow sphere A356 aluminum matrix composites
  43. Uniaxial compression stress–strain relationship of fully aeolian sand concrete at low temperatures
  44. Experimental study on the influence of aggregate morphology on concrete interfacial properties
  45. Intelligent sportswear design: Innovative applications based on conjugated nanomaterials
  46. Research on the equivalent stretching mechanical properties of Nomex honeycomb core considering the effect of resin coating
  47. Numerical analysis and experimental research on the vibration performance of concrete vibration table in PC components
  48. Assessment of mechanical and biological properties of Ti–31Nb–7.7Zr alloy for spinal surgery implant
  49. Theoretical research on load distribution of composite pre-tightened teeth connections embedded with soft layers
  50. Coupling design features of material surface treatment for ceramic products based on ResNet
  51. Optimizing superelastic shape-memory alloy fibers for enhancing the pullout performance in engineered cementitious composites
  52. Multi-scale finite element simulation of needle-punched quartz fiber reinforced composites
  53. Thermo-mechanical coupling behavior of needle-punched carbon/carbon composites
  54. Influence of composite material laying parameters on the load-carrying capacity of type IV hydrogen storage vessel
  55. Review Articles
  56. Effect of carbon nanotubes on mechanical properties of aluminum matrix composites: A review
  57. On in-house developed feedstock filament of polymer and polymeric composites and their recycling process – A comprehensive review
  58. Research progress on freeze–thaw constitutive model of concrete based on damage mechanics
  59. A bibliometric and content analysis of research trends in paver blocks: Mapping the scientific landscape
  60. Bibliometric analysis of stone column research trends: A Web of Science perspective
https://doi.org/10.1515/secm-2022-0242
Keywords for this article
concrete; aeolian sand; water–binder ratio; chloride ion; chloride diffusion mode
Creative Commons
BY 4.0

Articles in the same Issue

  1. Regular Articles
  2. Research on damage evolution mechanisms under compressive and tensile tests of plain weave SiCf/SiC composites using in situ X-ray CT
  3. Structural optimization of trays in bolt support systems
  4. Continuum percolation of the realistic nonuniform ITZs in 3D polyphase concrete systems involving the aggregate shape and size differentiation
  5. Multiscale water diffusivity prediction of plain woven composites considering void defects
  6. The application of epoxy resin polymers by laser induction technologies
  7. Analysis of water absorption on the efficiency of bonded composite repair of aluminum alloy panels
  8. Experimental research on bonding mechanical performance of the interface between cementitious layers
  9. A study on the effect of microspheres on the freeze–thaw resistance of EPS concrete
  10. Influence of Ti2SnC content on arc erosion resistance in Ag–Ti2SnC composites
  11. Cement-based composites with ZIF-8@TiO2-coated activated carbon fiber for efficient removal of formaldehyde
  12. Microstructure and chloride transport of aeolian sand concrete under long-term natural immersion
  13. Simulation study on basic road performance and modification mechanism of red mud modified asphalt mixture
  14. Extraction and characterization of nano-silica particles to enhance mechanical properties of general-purpose unsaturated polyester resin
  15. Roles of corn starch and gellan gum in changing of unconfined compressive strength of Shanghai alluvial clay
  16. A review on innovative approaches to expansive soil stabilization: Focussing on EPS beads, sand, and jute
  17. Experimental investigation of the performances of thick CFRP, GFRP, and KFRP composite plates under ballistic impact
  18. Preparation and characterization of titanium gypsum artificial aggregate
  19. Characteristics of bulletproof plate made from silkworm cocoon waste: Hybrid silkworm cocoon waste-reinforced epoxy/UHMWPE composite
  20. Experimental research on influence of curing environment on mechanical properties of coal gangue cementation
  21. Multi-objective optimization of machining variables for wire-EDM of LM6/fly ash composite materials using grey relational analysis
  22. Synthesis and characterization of Ag@Ni co-axial nanocables and their fluorescent and catalytic properties
  23. Beneficial effect of 4% Ta addition on the corrosion mitigation of Ti–12% Zr alloy after different immersion times in 3.5% NaCl solutions
  24. Study on electrical conductive mechanism of mayenite derivative C12A7:C
  25. Fast prediction of concrete equivalent modulus based on the random aggregate model and image quadtree SBFEM
  26. Research on uniaxial compression performance and constitutive relationship of RBP-UHPC after high temperature
  27. Experimental analysis of frost resistance and failure models in engineered cementitious composites with the integration of Yellow River sand
  28. Influence of tin additions on the corrosion passivation of TiZrTa alloy in sodium chloride solutions
  29. Microstructure and finite element analysis of Mo2C-diamond/Cu composites by spark plasma sintering
  30. Low-velocity impact response optimization of the foam-cored sandwich panels with CFRP skins for electric aircraft fuselage skin application
  31. Research on the carbonation resistance and improvement technology of fully recycled aggregate concrete
  32. Study on the basic properties of iron tailings powder-desulfurization ash mine filling cementitious material
  33. Preparation and mechanical properties of the 2.5D carbon glass hybrid woven composite materials
  34. Improvement on interfacial properties of CuW and CuCr bimetallic materials with high-entropy alloy interlayers via infiltration method
  35. Investigation properties of ultra-high performance concrete incorporating pond ash
  36. Effects of binder paste-to-aggregate ratio and polypropylene fiber content on the performance of high-flowability steel fiber-reinforced concrete for slab/deck overlays
  37. Interfacial bonding characteristics of multi-walled carbon nanotube/ultralight foamed concrete
  38. Classification of damping properties of fabric-reinforced flat beam-like specimens by a degree of ondulation implying a mesomechanic kinematic
  39. Influence of mica paper surface modification on the water resistance of mica paper/organic silicone resin composites
  40. Impact of cooling methods on the corrosion behavior of AA6063 aluminum alloy in a chloride solution
  41. Wear mechanism analysis of internal chip removal drill for CFRP drilling
  42. Investigation on acoustic properties of metal hollow sphere A356 aluminum matrix composites
  43. Uniaxial compression stress–strain relationship of fully aeolian sand concrete at low temperatures
  44. Experimental study on the influence of aggregate morphology on concrete interfacial properties
  45. Intelligent sportswear design: Innovative applications based on conjugated nanomaterials
  46. Research on the equivalent stretching mechanical properties of Nomex honeycomb core considering the effect of resin coating
  47. Numerical analysis and experimental research on the vibration performance of concrete vibration table in PC components
  48. Assessment of mechanical and biological properties of Ti–31Nb–7.7Zr alloy for spinal surgery implant
  49. Theoretical research on load distribution of composite pre-tightened teeth connections embedded with soft layers
  50. Coupling design features of material surface treatment for ceramic products based on ResNet
  51. Optimizing superelastic shape-memory alloy fibers for enhancing the pullout performance in engineered cementitious composites
  52. Multi-scale finite element simulation of needle-punched quartz fiber reinforced composites
  53. Thermo-mechanical coupling behavior of needle-punched carbon/carbon composites
  54. Influence of composite material laying parameters on the load-carrying capacity of type IV hydrogen storage vessel
  55. Review Articles
  56. Effect of carbon nanotubes on mechanical properties of aluminum matrix composites: A review
  57. On in-house developed feedstock filament of polymer and polymeric composites and their recycling process – A comprehensive review
  58. Research progress on freeze–thaw constitutive model of concrete based on damage mechanics
  59. A bibliometric and content analysis of research trends in paver blocks: Mapping the scientific landscape
  60. Bibliometric analysis of stone column research trends: A Web of Science perspective
Sign up now to receive a 20% welcome discount
Institutional Access
How does access work?
Have an idea on how to improve our website?
Please write us.
© 2025 De Gruyter Brill
Downloaded on 11.9.2025 from https://www.degruyterbrill.com/document/doi/10.1515/secm-2022-0242/html
Scroll to top button