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Article

Impermeability, Strength and Microstructure of Concrete Modified by Nano-Silica and Expansive Agent

by
Pinmo Zeng
,
Mohammed A. A. M. Abbas
,
Xinyi Ran
and
Peipeng Li
*
School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan 430070, China
*
Author to whom correspondence should be addressed.
J. Compos. Sci. 2025, 9(3), 108; https://doi.org/10.3390/jcs9030108
Submission received: 1 January 2025 / Revised: 13 February 2025 / Accepted: 21 February 2025 / Published: 25 February 2025
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Abstract

:
The impermeability of concrete is very important to its durability and service life, which could be affected by nanomaterial and mineral admixture additions. This paper tends to enhance the impermeability, strength, and microstructure of concrete using nano-silica (NS) and U-type expansive agent (UEA). The slump flow, compressive strength, chloride ion resistance, water penetration and absorption, hydration, and microstructure of concrete are investigated under different NS and UEA contents. The results indicate that an appropriate NS content of 2% contributes to dense pore structure and the generation of more hydration product for impermeability-enhanced concrete, which results in a compressive strength of 43.53 MPa and chloride ion and water penetration resistance improvements of 21% and 35%, respectively. The slump flow and compressive strength of concrete decrease slightly in the presence of UEA utilization, while the chloride ion and water penetration resistances are firstly enhanced and then weakened with the increase in UEA contents. In the case of 9% UEA, the concrete achieves a compressive strength of 31.54 MPa, a chloride ion penetration coefficient of 9.34 × 10−12 m2/s, and a relative permeability coefficient of 2.56 cm/s.

1. Introduction

With the development of society, the application of concrete materials in the field of construction engineering has become increasingly widespread [1,2]. However, due to the long-term exposure of concrete to external environments, water or corrosive ions can infiltrate into the concrete through physical or chemical effects, leading to the degradation of concrete, which can result in issues such as cracking and reinforcement corrosion [3,4,5,6]. Research has shown that when concrete undergoes freezing, the pressure associated with the movement of water inside the concrete is not only governed by its permeability but also affects the critical saturation of the concrete, thereby influencing its freeze–thaw resistance [7]. Zhang et al. [8] found that in concrete with poor permeability, CO2 from the atmosphere diffuses from the outside to the inside of the concrete, reacting with the internal alkaline substances, which accelerates the carbonation of the concrete. In recent years, researchers have found that the addition of admixtures and other measures to concrete can significantly enhance its impermeability, which is of great importance for improving the durability of concrete [9].
The addition of nanomaterials or expansive agents to concrete can significantly enhance its various properties [10,11,12]. Research by Jalal et al. [13] shows that the composite addition of fly ash and nano-silica significantly improves the splitting tensile strength and compressive strength of self-compacting concrete. Said et al. [14] studied the effects of nano-silica on pure cement materials and cement–fly ash composite materials, finding that the incorporation of silica resulted in some improvement in the concrete’s strength, pore structure, and interface transition zone. Mohammed et al. [15] found that a moderate amount of nano-silica added to rubberized concrete could offset the decrease in compressive strength, resulting in the best performance of rubberized concrete. Guo et al. [16] demonstrated that the inclusion of UEA expansive agents significantly enhanced the fracture resistance of concrete. Zhang et al. [17] showed that the addition of UEA expansive agents improved the chloride ion permeability of concrete, and over time, the reduction in compressive strength became less significant, with the compressive strength at 56 days remaining consistent with the control group. Studies have shown that after the hydration of UEA expansive agents in concrete, the generated ettringite can cause internal expansion, and in practical construction, this characteristic can be utilized for seamless construction, thus improving the crack resistance and impermeability of concrete.
In summary, both NS and UEA expansive agents could enhance the mechanical properties and microstructure of concrete. However, their specific microscopic mechanisms on impermeability remain unclear. This study investigates the macroscopic impact and microscopic mechanisms of NS and UEA expansive agents on the impermeability of C35 concrete through the addition of varying contents of NS and UEA expansive agents. This study provides a theoretical basis for the practical application of impermeable concrete from both macroscopic and microscopic perspectives.

2. Experimental Program

2.1. Raw Materials

The cementitious materials used in this study include ordinary Portland 42.5 cement, fly ash, S95 slag powder based on GB/T 18046-2017 [18], nano-silica (NS), and UEA (united or u-type expansive agent). The main chemical composition of the cement is shown in Table 1, while the key properties of the NS are detailed in Table 2, respectively. In order to reduce the physical agglomeration effect of NS, this study used a commercial colloidal NS with a content of about 30% in the solution. UEA is a common expansion agent to form expansive hydration products such as ettringite; the UEA we used was from the Hongxiang Construction Admixture Factory in Laiyang City, China. Artificial machine-made sand with a fineness modulus of 2.8 is used as the fine aggregate, while the coarse aggregate is natural crushed stone with a particle size of 5–20 mm. A polycarboxylate-based superplasticizer with a water-reducing efficiency of 26% is used to enhance workability.

2.2. Experimental Design

In this study, a single variable method is used to design 7 groups of different concrete mix ratios. To investigate the effects of NS content on the performance of C35 concrete, three solid NS dosage levels are selected: 1%, 2%, and 3% (relative to the mass of the cementitious materials, hereafter the same). Similarly, to study the influence of the UEA expansive agent on C35 concrete properties, three dosage levels are chosen: 6%, 9%, and 12%, respectively. The detailed mix ratio is shown in Table 3.

2.3. Testing Methods

The slump test for concrete was conducted according to GB/T 50080-2016 [19]. The compressive strength and water absorption tests were carried out according to GB/T 50081-2019 [20]. For these tests, cubic specimens with a side length of 100 mm were used. The water penetration resistance and chloride ion penetration resistance tests were carried out based on GB/T 50082-2009 [21]. Microstructure and hydration analysis of the corresponding paste to each concrete group without any aggregate was analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG), and nitrogen adsorption tests. The composition was analyzed by the Panalytical Empyrean X-ray diffractometer (The instruments are manufactured by Malvern Panalytical in Shanghai, China.), the paste samples were scanned at a scanning speed of 5°/min, and the scanning range was 5~90°. The morphology was characterized by scanning electron microscopy (SEM) using the Sigma 300 instrument (The equipment is produced by Zeiss, from Oberkohen, Germany). The thermal stability of the paste samples was evaluated by the PerkinElmer STA 6000 thermogravimetric analyzer (The equipment is produced by Perkin Elmer Enterprise Management Co., Ltd., from Shanghai, China). The heating rate was 10 °C/min, and the temperature range was 30~800 °C. The nitrogen adsorption test (BET) was performed using the TriStar II 3flex instrument (The equipment was produced by McMurray Tik Instrument Co., Ltd., from Shanghai, China) to test and analyze its nanoscale pore size distribution in the range of 2–50 nm.

3. Experimental Results and Analysis

3.1. Workability

Figure 1 and Figure 2 show the variation in concrete slump with increasing contents of NS and UEA expansive agents, respectively. As shown in Figure 1, the slump of concrete decreases with increasing NS content. Compared to the control group, the slumps of NS-1, NS-2, and NS-3 decrease by 27.8%, 44.4%, and 71.1%, respectively. This reduction is attributed to the nanoscale particle size and high specific surface area of NS, which adsorbs a significant amount of free water in the concrete mixture, resulting in a decrease in its slump [9]. Figure 2 shows that the slump of concrete also decreases with the addition of UEA expansive agent, but this is at a slower rate compared to the NS group. Compared with the reference group, the slump of concrete with 6% UEA decreases by 16.7%. The UEA expansive agent contains reactive components that react with Ca(OH)2 in the cementitious materials to form products such as ettringite. This accelerates early hydration of the material, leading to a decrease in the concrete slump [22].

3.2. Compressive Strength

Figure 3 shows the compressive strength of concrete specimens with NS incorporation after 28 days of standard curing. It can be seen that the compressive strength of the control group is 35.7 MPa. When the NS content is 1%, 2%, and 3% of the cementitious materials, the compressive strengths of the concrete are 40.3 MPa, 43.5 MPa, and 36.9 MPa, respectively, representing increases of 12.8%, 21.9%, and 3.2% compared to the control group. This improvement is due to two factors. First, the extremely fine particles of NS act as a physical filler, refining the micro-pore structure within the concrete and enhancing its strength. Second, NS exhibits high pozzolanic activity, which allows it to react with the hydration products of cement, such as Ca(OH)2, in a secondary hydration process. This reaction generates more C-S-H gel, promoting the development of the concrete’s mechanical properties [23]. However, with the increase in NS content, a decrease in concrete strength is observed. Due to the strong hydrophilicity of NS particles, excessive incorporation can lead to agglomeration. This agglomeration traps some free water within the NS clusters, reducing the amount of water available for cement hydration, which reduces the compressive strength of the concrete.
Figure 4 shows the compressive strength of concrete specimens with UEA expansive agent after 28 days of curing. The addition of UEA expansive agent leads to a slight decrease in the mechanical properties of the concrete. When the UEA expansive agent content is 6%, 9%, and 12% by mass of the cementitious materials, the compressive strengths of the concrete are 31.2 MPa, 31.5 MPa, and 31.8 MPa, respectively, representing reductions of 12.8%, 11.7%, and 10.9% compared to the control group. The UEA expansive agent could react with Ca(OH)2 to form a large amount of ettringite crystals, which could be demonstrated by the SEM observation below. These ettringite crystals generally appear in columnar or needle-like crystals, and the framework structure formed by the interlocking of these crystals contains numerous pores, which negatively affect the development of concrete strength. Additionally, the expansive stress generated by the UEA expansive agent exceeds the tensile stress within the concrete, resulting in compressive damage and bringing in microcracks, which reduces the compressive strength of the concrete [17].

3.3. Chloride Ion Penetration Resistance

The chloride ion penetration test results for the various concrete groups are shown in Figure 5 and Figure 6. As can be seen from the figures, with the addition of NS, the chloride ion penetration depth of the concrete gradually decreases. For concrete specimens containing UEA, the chloride ion penetration depth initially decreases and then increases as the UEA dosage increases. Figure 7 shows the 28 d unsteady chloride ion migration coefficients for the NS groups. It can be seen that when the NS content is 3%, the unsteady chloride ion migration coefficient of the concrete is 5.41 × 10−12 m2/s, a 45% reduction compared to the control group. The pozzolanic activity of NS and its particle accumulation effect refine the pore structure inside the concrete, significantly improving its density and effectively blocking the interconnected pores in the matrix. This results in a hindrance to the diffusion of chloride ions within the concrete [24].
The 28 d unsteady chloride ion migration coefficients for concrete specimens with UEA expansive agent are shown in Figure 8. It can be seen that as the UEA expansive agent content increases, the unsteady chloride ion migration coefficient initially decreases and then increases. When the expansive agent content is 9% of the cementitious materials, the unsteady chloride ion migration coefficient of the concrete is 9.34 × 10−12 m2/s, a reduction of 11% compared to the control group. This improvement can be attributed to the reaction of the UEA expansive agent with water in the concrete, forming expansive crystalline hydration products. The resulting compressive stress counteracts the tensile stress generated during the drying shrinkage of the concrete, thereby preventing and reducing cracking and improving the compactness of the concrete. Furthermore, the nitrogen adsorption test results, as shown below, indicate that the addition of UEA expansive agent reduces the concrete’s porosity and refines the pore structure, enhancing its resistance to chloride ion penetration [25]. However, when the expansive agent content is increased to 12%, the chloride ion penetration resistance improves only by 2%. This is likely because excessive amounts of the expansive agent cause significant volume expansion in the concrete, leading to the formation of more microcracks, which reduce the concrete’s resistance to chloride ion penetration [26].

3.4. Water Permeability Resistance

The results of the water penetration resistance tests for the various concrete groups are shown in Figure 9 and Figure 10. After the addition of NS or UEA expansive agent, the water penetration resistance depth of the concrete decreases to varying degrees. The relative permeability coefficients for the NS group are shown in Figure 11. It can be seen that after the incorporation of NS into the concrete, the relative permeability coefficient initially decreases and then increases. When the NS content is 2%, the relative permeability coefficient of the concrete is 1.09 cm/s, which is an 82% reduction compared to the control group. This improvement can be attributed to the secondary hydration reaction of NS with Ca(OH)2, which generates more C-S-H gel. This reaction densifies the interfacial transition zone within the concrete, greatly enhancing its resistance to water penetration [27]. However, when the NS content reaches 3%, the reduction in permeability significantly decreases, with a 62% decrease compared to the control group. This is because an excessive content of NS may cause uneven dispersion and agglomeration, reducing the available free water for hydration reactions. As a result, the hydration of the cementitious materials slows down, leading to a less significant improvement in the concrete’s water permeability resistance.
Figure 12 shows the relative permeability coefficient for concrete specimens with the addition of UEA expansive agent after 28 days. As the content of UEA expansive agent increases, the relative permeability coefficient of the concrete initially decreases and then increases. When the content of UEA expansive agent is 9% of the cementitious materials, the relative permeability coefficient of the concrete is 2.55 cm/s, a reduction of 58% compared to the control group. This improvement is due to the fact that the moderate addition of the expansive agent leads to the generation of crystallization expansion products that compensate for concrete shrinkage, making the concrete denser and enhancing its resistance to water penetration. When the dosage of the expansive agent increases to 12%, the relative permeability coefficient only decreases by 8% compared to the control group, indicating a significant reduction in the extent of improvement in the concrete’s water permeability. This is because the UEA expansive agent reacts with Ca(OH)2 in the cement hydration products, leading to the formation of too much ettringite, which causes the growth of larger voids within the concrete [26]. This process results in a decrease in the concrete’s resistance to water penetration.

3.5. Water Absorption Performance

Figure 13 and Figure 14 show the variation curves of the water absorption mass for concrete containing NS and UEA expansive agents, respectively. As can be observed, the water absorption quality of each concrete specimen initially increases and then tends to be stable. During the initial phase of water absorption, the large pores inside the concrete penetrate most of the water. After a certain period, the water absorption gradually reaches saturation, and the quality of concrete gradually remains stable [28,29].
Figure 15 shows the change in the water absorption rate of the NS group. It can be seen that as the NS content increases, the water absorption rate initially decreases and then increases, which is consistent with the previously observed water permeability resistance performance. When the NS content is 2%, the concrete achieves the lowest water absorption rate of 3.52%, which is a reduction of 16% compared to the control group. The appropriate addition of NS not only serves a filling role but also promotes secondary hydration of the cement, resulting in the formation of more C-S-H gel, which refines the pore structure of the concrete. Figure 16 displays the water absorption rate variation for concrete specimens containing UEA expansive agent. The UEA expansive agent is shown to reduce the water absorption rate of concrete. When the expansive agent content is 6%, 9%, and 12%, the concrete water absorption rate is 3.57%, 3.38%, and 3.62%, respectively. During the reaction process within the concrete, the crystalline expansion products generated by the expansive agent compensate for the shrinkage of the concrete, making it denser and thus reducing its water absorption rate.

3.6. XRD Analysis

Figure 17 and Figure 18 show the XRD patterns of concrete pastes containing NS and UEA after 28 days of standard curing, respectively. Figure 17 shows that in the control group of concrete paste without NS, the peak values of unreacted C2S/C3S and the hydration product Ca(OH)2 are significantly higher than those in the specimens with NS. This suggests that, in the unmodified specimens, some cement particles remain unhydrated even after 28 days. The hydration products of cement are mostly Ca(OH)2, which has relatively low strength. In contrast, the peak values of Ca(OH)2 and C2S/C3S with 2% NS decreased significantly, while the peak value of C-S-H increased significantly, and the peak value of AFt decreased. This indicates that the highly pozzolanic activity of NS reacts with the primary hydration product Ca(OH)2, producing C-S-H gel, while a small amount of Ca(OH)2 reacts to form calcium aluminate. The secondary hydration reaction is well developed in the matrix, with the peaks for unhydrated clinker and Ca(OH)2 being significantly suppressed. This results in enhanced concrete performance, consistent with the macro-performance test results discussed above.
From Figure 18, it can be seen that in the concrete pastes containing UEA expansive agent, the diffraction peaks for Ca(OH)2 and C2S/C3S show a downward trend, while the diffraction peaks of AFt show an upward trend. This is mainly because UEA is a sulfate-aluminate expansive agent, which reacts with the primary hydration product Ca(OH)2 to form a significant amount of ettringite [17]. At the same time, the decrease in the Ca(OH)2 content further promotes the hydration of cement. Therefore, after the addition of UEA, the diffraction peaks for Ca(OH)2 decrease, while the AFt peak increases noticeably.

3.7. Microstructure Analysis

Figure 19 shows the SEM images of the concrete pastes after 28 days of standard curing. In Figure 19a, the matrix contains a large amount of primary cement hydration product Ca(OH)2. The accumulation of Ca(OH)2 crystals leads to a loose matrix structure, which is not conducive to the mechanical and durability performance of cement-based materials. However, the addition of NS helps to improve the microstructure. Figure 19b,c show the microstructures of specimens with 2% and 3% NS, respectively. NS reacts with Ca(OH)2 in the matrix in a pozzolanic reaction, reducing the content of Ca(OH)2 crystals and generating more C-S-H gel. Compared to Figure 19a, the Ca(OH)2 crystals in Figure 19b,c are significantly reduced. The secondary hydration reaction generates C-S-H gel, making the microstructure of the concrete matrix denser. Therefore, the addition of NS improves both the mechanical and permeability resistance performance of the concrete.
The microstructure of the matrix after the addition of UEA is shown in Figure 19d,e. Compared to the control group, the microstructure of the concrete paste with UEA becomes looser, with many needle-like AFt crystal phases appearing. UEA reacts with the cement hydration product Ca(OH)2 to form a large number of ettringite (AFt) crystals. Figure 19e shows the microstructure of the specimen with 12% UEA. The extensive interlocking of the needle-like AFt crystals creates numerous pores. This loose and porous microstructure is unfavorable for the development of the mechanical properties of the concrete. Therefore, the addition of UEA leads to a decline in the concrete’s mechanical performance.

3.8. TG-DTG Analysis

Figure 20 shows the TG and DTG curves of three different paste samples (control group, NS-2, and UEA-9). The NS-2 group shows the least mass loss. In contrast, the UEA-9 group exhibits the greatest mass loss. This indicates that the addition of NS improves the thermal stability of the concrete, whereas the UEA expansive agent reduces the thermal stability of the concrete matrix. Analyzing the DTG curve in Figure 20b, two distinct peaks are observed within the temperature range of 30–800 °C. The first and second peaks appear around 100 °C, which correspond to the evaporation of free water and the initial dehydration of silicate materials in the sample. The third peak appears around 400–500 °C, which is related to the dehydration of Ca(OH)2 in the sample. From the curve, it can be seen that the Ca(OH)2 peak in the control group is the highest, indicating the highest content of Ca(OH)2, while the peaks for the NS-2 and UEA-9 groups are relatively smaller, with the NS-2 group showing the lowest peak, signifying the least amount of Ca(OH)2. The reduction in the thermal decomposition peak of Ca(OH)2 indicates that both NS and UEA can react with the cement hydration product Ca(OH)2, promoting hydration reactions within the concrete matrix. This finding is consistent with the previously observed microstructural phenomena.

3.9. Pore Structure Analysis

Figure 21 shows the pore size distribution and cumulative pore volume of each group of concrete pastes after 28 days of standard curing. It is shown that both the NS and UEA groups exhibit a critical peak in the pore size distribution, which appears around 3.4 nm.
From Figure 21a, it can be seen that the control group has the highest peak value, while the NS-2 group shows the lowest peak intensity, indicating that the addition of NS reduces the pore volume. Figure 22 displays the cumulative pore volume for each mixture. From the analysis of Figure 22a, it can be seen that the inclusion of NS significantly reduces the total porosity. This is because NS, with its pozzolanic activity, can undergo secondary hydration reactions with Ca(OH)2 in the matrix, further increasing the C-S-H gel content, thereby reducing the internal porosity [28].
By analyzing Figure 21b, it can be seen that the control group has the highest peak value, and the UEA-12 group has the lowest peak intensity, suggesting that the addition of UEA expansive agent reduces the pore volume of the concrete. From Figure 22b, it is observed that the addition of 9% UEA expansive agent reduces the total porosity of the concrete, but the inclusion of 12% UEA expansive agent leads to an increase in total porosity. This could be due to the significant volumetric expansion that occurs when UEA reacts with Ca(OH)2 to form ettringite, which results in the formation of numerous microcracks and an increase in the porosity of the specimen.

4. Conclusions

(1)
The addition of NS can improve the 28 d compressive strength, water permeability, water absorption, and chloride ion permeability of concrete. The strength of concrete specimens with 2% NS shows a 21.9% increase in strength, a 21.0% reduction in the chloride ion permeability coefficient, a 35.0% decrease in the relative permeability coefficient, and an 8.8% uction in water absorption. A higher dosage of NS can lead to agglomeration, resulting in degraded performance. Considering both mechanical properties and impermeability, it is recommended that the suitable dosage of NS is 2%.
(2)
NS exhibits excellent pozzolanic activity, reacting with the primary hydration product Ca(OH)2 to form C-S-H gel. The physical filling effect and secondary hydration reaction of NS significantly refine the pore structure of the concrete, improving both its mechanical and impermeability properties. According to the TG test results, the addition of NS enhances the thermal stability of concrete.
(3)
The addition of an expansive agent reduces the 28-day compressive strength of concrete; however, an appropriate amount of expansive agent can improve the concrete’s resistance to water and chloride ion penetration as well as reduce its water absorption. When the UEA expansive agent content is 9%, the concrete’s relative permeability coefficient, chloride ion permeability coefficient, and water absorption improve by 58%, 11%, and 20%, respectively.
(4)
The UEA expansive agent reacts with Ca(OH)2 to form AFt, which reduces the porosity of the concrete matrix. However, when the dosage of the expansive agent is too high, excessive volume expansion results in numerous microcracks, increasing the porosity and deteriorating the concrete’s performance. To ensure that concrete retains excellent properties after the addition of UEA expansive agent, the dosage should not exceed 9%.
(5)
The addition of appropriate contents of NS and UEA in concrete could improve the impermeability, strength, and microstructure. NS at 2% or UEA at 9% is suggested for an impermeability-enhanced concrete application.

Author Contributions

Conceptualization, P.Z. and P.L.; methodology, P.Z. and P.L.; formal analysis, P.Z.; investigation, P.Z.; data curation, P.Z.; writing—original draft, P.Z.; writing—review and editing, M.A.A.M.A., X.R. and P.L.; supervision, P.L. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

Data are contained within the article.

Acknowledgments

The authors express their gratitude to the testing support from Shiyanjia ab (https://www.shiyanjia.com (accessed on 26 June 2024)).

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Monticelli, C.; Frignani, A.; Trabanelli, G. A study on corrosion inhibitors for concrete application. Cem. Concr. Compos. 2000, 30, 635–642. [Google Scholar] [CrossRef]
  2. Chica, L.; Alzate, A. Cellular concrete review: New trends for application in construction. Constr. Build. Mater. 2019, 200, 637–647. [Google Scholar] [CrossRef]
  3. Meng, X.; Feng, Q.; Zhang, Y.; Qiao, H.; Xie, X. Analysis of corrosion-induced deterioration behavior and competing failure of reinforced concrete in saline soil environment. Mater. Rep. 2023, 37, 40–49. [Google Scholar] [CrossRef]
  4. Rathore, P.; Verma, S.K. Carbonation based deterioration of concrete structures and effect of carbonation curing. Int. J. Struct. Eng. 2023, 13, 279–300. [Google Scholar] [CrossRef]
  5. Yamin, A.; Ahmet, R.; Oğuz, B.; Düzgün, A. Concrete deterioration effects on dynamic behavior of gravity dam-reservoir interaction problems. J. Vib. Eng. Technol. 2024, 12, 259–278. [Google Scholar] [CrossRef]
  6. Luo, D.; Li, F.; Niu, D. Study on the deterioration of concrete performance in saline soil area under the combined effect of high low temperatures, chloride and sulfate salts. Cem. Concr. Compos. 2024, 150, 105531. [Google Scholar] [CrossRef]
  7. Cao, Q.; Gao, Q.; Gao, R.; Jia, J. Chloride penetration resistance and frost resistance of fiber reinforced expansive self-consolidating concrete. Constr. Build. Mater. 2018, 158, 719–727. [Google Scholar] [CrossRef]
  8. Zhang, D.; Shao, Y. Effect of early carbonation curing on chloride penetration and weathering carbonation in concrete. Constr. Build. Mater. 2016, 123, 516–526. [Google Scholar] [CrossRef]
  9. Lu, S.; Wang, M.; He, P.; Sun, X.; Wang, X.; Tang, D. Effect of sodium methyl-silicate on the performance and structure of geopolymer. Mater. Lett. 2023, 350, 134893. [Google Scholar] [CrossRef]
  10. Kansotiya, M.; Chaturvedy, G.K.; Pandey, U.K. Influence of nano silica and crumb rubber on the physical and durability characteristics of concrete. Multiscale Multidiscip. Model. Exp. Des. 2024, 7, 2877–2892. [Google Scholar] [CrossRef]
  11. Ghafari, E.; Arezoumandi, M.; Costa, H.; Júlio, E. Influence of nano-silica addition on durability of UHPC. Constr. Build. Mater. 2015, 94, 181–188. [Google Scholar] [CrossRef]
  12. Wang, Q.; Ren, Z.; Zhang, Z. Study on the delayed ettringite formation in massive shrinkage compensating concrete with U-type expansive agent. Key Eng. Mater. 2011, 477, 340–347. [Google Scholar] [CrossRef]
  13. Jalal, M.; Pouladkhan, A.R.; Ramezanianpour, A.A.; Norouzi, H. Effects of silica nanopowder and silica fume on rheology and strength of high strength self compacting concrete. J. Am. Sci. 2012, 8, 270–277. [Google Scholar]
  14. Said, A.M.; Zeidan, M.S.; Bassuoni, M.T.; Tian, Y. Properties of concrete incorporating nano-silica. Constr. Build. Mater. 2012, 36, 838–844. [Google Scholar] [CrossRef]
  15. Mohammed, B.S.; Adamu, M. Mechanical performance of roller compacted concrete pavement containing crumb rubber and nano silica. Constr. Build. Mater. 2018, 159, 234–251. [Google Scholar] [CrossRef]
  16. Guo, J.; Zhang, S.; Guo, T.; Zhang, P. Effects of UEA and MgO expansive agents on fracture properties of concrete. Constr. Build. Mater. 2020, 263, 120245. [Google Scholar] [CrossRef]
  17. Zhang, J.; Zhang, J.; Xiao, W.; Wang, Q.; Shao, F. Experimental study on the effect of expansive agent on the durability of concrete in civil air defense engineering. Adv. Mater. Sci. Eng. 2021, 2021, 1–7. [Google Scholar] [CrossRef]
  18. GB/T18046-2017; Granulated blast furnace slag powder for use in cement, mortar and concrete. Standards Press of China: Beijing, China, 2018. (In Chinese)
  19. GB/T50080-2016; Standard for Performance Test Method of Ordinary Concrete Mixture. China Architecture and Building Press: Beijing, China, 2017. (In Chinese)
  20. GB/T50081-2019; Standard for Test Method of Mechanical Properties on Ordinary Concrete. China Architecture and Building Press: Beijing, China, 2019. (In Chinese)
  21. GB/T50082-2009; Standard for Test Methods for Long-Term Performance and Durability of Ordinary Concrete. China Architecture and Building Press: Beijing, China, 2010. (In Chinese)
  22. Mahmood, A.; Kaish, A.B.M.A.; Raman, S.N.; Jamil, M.; Hamid, R. Effects of different expansive agents on the properties of expansive cementitious materials. IOP Conf. Ser. Mater. Sci. Eng. 2021, 1200, 012002. [Google Scholar] [CrossRef]
  23. Khan, K.; Ahmad, W.; Amin, M.N.; Nazar, S. Nano-silica-modified concrete: A bibliographic analysis and comprehensive review of material properties. Nanomaterials 2022, 12, 1989. [Google Scholar] [CrossRef]
  24. Aggarwal, P.; Singh, R.P.; Aggarwal, Y. Use of nano-silica in cement-based materials—A review. Cogent Eng. 2015, 2, 1078018. [Google Scholar] [CrossRef]
  25. Materak, K.; Wieczorek, A.; Bednarska, D.; Cha, K.; Ma, M.; Buczkowski, A.; Koniorczyk, M. Novel application of potassium methylsiliconate in cement-based materials: Retarding of hydration process and improvement of compressive strength. Constr. Build. Mater. 2023, 406, 133400. [Google Scholar] [CrossRef]
  26. Gao, P.; Geng, F.; Lu, X. Hydration and expansion properties of novel concrete expansive agent. Key Eng. Mater. 2009, 406, 267–271. [Google Scholar] [CrossRef]
  27. Chen, X.; Chen, Y. Experimental study on damage identification of nano-SiO2 concrete filled GFRP tube column using piezo-ceramic transducers. Sensors 2020, 20, 2883. [Google Scholar] [CrossRef] [PubMed]
  28. Gao, J.; Li, S.C.; Zhang, W.F.; Geng, Y.J.; Xiao, Q.L.; Hou, D.S. Effect of isobutyltriethoxysilane composite latex on waterproofing properties of foam concrete. Paint Coat. Ind. 2020, 50, 2–7. [Google Scholar] [CrossRef]
  29. Li, P.P.; Brouwers, H.J.H.; Chen, W.; Yu, Q. Optimization and characterization of high-volume limestone powder in sustainable ultra-high performance concrete. Constr. Build. Mater. 2020, 242, 118112. [Google Scholar] [CrossRef]
Jcs 09 00108 g001
Figure 1. Slump flow of NS group concrete.
Figure 1. Slump flow of NS group concrete.
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Figure 2. Slump flow of UEA group concrete.
Figure 2. Slump flow of UEA group concrete.
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Figure 3. Compressive strength of NS group concrete.
Figure 3. Compressive strength of NS group concrete.
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Figure 4. Compressive strength of UEA group concrete.
Figure 4. Compressive strength of UEA group concrete.
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Figure 5. Phenomenon of chloride ion penetration resistance test of NS group concrete.
Figure 5. Phenomenon of chloride ion penetration resistance test of NS group concrete.
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Figure 6. Phenomenon of chloride ion penetration resistance test of UEA group concrete.
Figure 6. Phenomenon of chloride ion penetration resistance test of UEA group concrete.
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Figure 7. Chloride migration coefficients of NS group concrete.
Figure 7. Chloride migration coefficients of NS group concrete.
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Figure 8. Chloride migration coefficients of UEA group concrete.
Figure 8. Chloride migration coefficients of UEA group concrete.
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Figure 9. Phenomenon of water permeability resistance in NS group.
Figure 9. Phenomenon of water permeability resistance in NS group.
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Figure 10. Phenomenon of water permeability resistance in UEA group.
Figure 10. Phenomenon of water permeability resistance in UEA group.
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Figure 11. Relative permeability coefficient of NS group concrete.
Figure 11. Relative permeability coefficient of NS group concrete.
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Figure 12. Relative permeability coefficient of UEA group concrete.
Figure 12. Relative permeability coefficient of UEA group concrete.
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Figure 13. Water absorption quality of NS group concrete.
Figure 13. Water absorption quality of NS group concrete.
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Figure 14. Water absorption quality of UEA group concrete.
Figure 14. Water absorption quality of UEA group concrete.
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Figure 15. Water absorption of NS group concrete.
Figure 15. Water absorption of NS group concrete.
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Figure 16. Water absorption of UEA group concrete.
Figure 16. Water absorption of UEA group concrete.
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Figure 17. XRD images of NS group specimen.
Figure 17. XRD images of NS group specimen.
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Figure 18. XRD images of UEA group specimen.
Figure 18. XRD images of UEA group specimen.
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Figure 19. SEM images of specimens: (a) reference group; (b) 2% nano-silica (NS-2) content experimental group; (c) 3% nano-silica content (NS-3) experimental group; (d) 9% U-type expansive agent (UEA-9) experimental group; and (e) 12% U-type expansive agent (UEA-12) content experimental group.
Figure 19. SEM images of specimens: (a) reference group; (b) 2% nano-silica (NS-2) content experimental group; (c) 3% nano-silica content (NS-3) experimental group; (d) 9% U-type expansive agent (UEA-9) experimental group; and (e) 12% U-type expansive agent (UEA-12) content experimental group.
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Figure 20. TG-DTG analysis of specimens: (a) TG (Thermogravimetry) curves; and (b) DTG (Derivative thermogravimetric) curves.
Figure 20. TG-DTG analysis of specimens: (a) TG (Thermogravimetry) curves; and (b) DTG (Derivative thermogravimetric) curves.
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Figure 21. Pore size distribution of specimen: (a) Nano-silica (NS) experimental group; and (b) U type expansion agent (UEA) experimental group.
Figure 21. Pore size distribution of specimen: (a) Nano-silica (NS) experimental group; and (b) U type expansion agent (UEA) experimental group.
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Figure 22. Cumulative pore volume of specimen: (a) Nano-silica (NS) experimental group; and (b) U type expansion agent (UEA) experimental group.
Figure 22. Cumulative pore volume of specimen: (a) Nano-silica (NS) experimental group; and (b) U type expansion agent (UEA) experimental group.
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Table 1. Main chemical composition of cement (%).
Table 1. Main chemical composition of cement (%).
CaOSiO2Al2O3Fe2O3MgOR2OSO3Loss
57.7424.566.353.973.520.342.151.37
Table 2. Main properties of the commercial NS product.
Table 2. Main properties of the commercial NS product.
SiO2/%Na2O/%Specific GravityViscositypHMean Diameter/(nm)
29.700.121.1923.397.4514.7
Table 3. Concrete mix design (kg/m3).
Table 3. Concrete mix design (kg/m3).
No.CementSlagFly AshNSUEASandAggregateWaterSuperplasticizer
Ref (NS-0/UEA-0)19080700080010541701.7
NS-119080703.4080010541701.7
NS-219080706.8080010541701.7
NS-3190807010.2080010541701.7
UEA-61908070020.480010541701.7
UEA-91908070030.680010541701.7
UEA-121908070040.880010541701.7
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MDPI and ACS Style

Zeng, P.; Abbas, M.A.A.M.; Ran, X.; Li, P. Impermeability, Strength and Microstructure of Concrete Modified by Nano-Silica and Expansive Agent. J. Compos. Sci. 2025, 9, 108. https://doi.org/10.3390/jcs9030108

AMA Style

Zeng P, Abbas MAAM, Ran X, Li P. Impermeability, Strength and Microstructure of Concrete Modified by Nano-Silica and Expansive Agent. Journal of Composites Science. 2025; 9(3):108. https://doi.org/10.3390/jcs9030108

Chicago/Turabian Style

Zeng, Pinmo, Mohammed A. A. M. Abbas, Xinyi Ran, and Peipeng Li. 2025. "Impermeability, Strength and Microstructure of Concrete Modified by Nano-Silica and Expansive Agent" Journal of Composites Science 9, no. 3: 108. https://doi.org/10.3390/jcs9030108

APA Style

Zeng, P., Abbas, M. A. A. M., Ran, X., & Li, P. (2025). Impermeability, Strength and Microstructure of Concrete Modified by Nano-Silica and Expansive Agent. Journal of Composites Science, 9(3), 108. https://doi.org/10.3390/jcs9030108

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