ARTICLE

Effect of silica sol on mechanical and shrinkage properties of alkali-activated slag-bonded clay

This paper explores the use of silica sol as an admixture for enhancing the performance of alkali-activated slag-bonded clay (AASC). In this system, clay plays both a filler role and participates in hydration reactions by retaining water and releasing active ions (e.g., Ca2+), which influences ion distribution, microstructure, and stability. Experimental results demonstrate that silica sol is capable of promoting the early hydration of AASC by providing additional reactive nano-sized SiO2 and nucleation sites, thereby shortening the setting time. However, at higher dosages, silica sol may also inhibit the hydration process due to the densification of the microstructure, which hinders ion diffusion and reduces the availability of reactive sites. Moreover, nano-sized SiO2 contributes to the refinement of the pore structure, contributing to the densification of the microstructure and subsequently increasing the compressive strength of AASC. More importantly, incorporating silica sol can effectively reduce the shrinkage of AASC. An appropriate dosage of silica sol results in a 21% improvement in compressive strength at 7d and 21% at 28d for AASC mortar, while the drying shrinkage is decreased by 13.9% compared to that of the control mortar.

1 Introduction

Throughout the long history of humanity, earthen building, with clay as the construction material, has been a prevalent form of construction, providing shelter and indoor environments that protect people from the wind and rain [1, 2]. Nevertheless, this kind of building

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Yifan Liu1, Wenwen Luo1, Liping Wang1,*, Qingru Xu2, Wenjie Wu1, Peiyuan Chen2
1School of Civil and Hydraulic Engineering, Chongqing University of Science and Technology, China
2School of Civil Engineering and Architecture, Anhui University of Science and Technology, China
*Corresponding Author: Liping Wang. Email: wangliping98@163.com

REFERENCES

1. Sánchez-Calvillo A, Rincón L, Hamard E, Faria P. Bibliometric analysis on earthen building: approaches from the scientific literature and future trends. Buildings. 2024;14(12):3870. doi:10.3390/buildings14123870.

2. Zhang Y, Jiang S, Quan D, Fang K, Wang B, Ma Z. Properties of sustainable earth construction materials: a state-of-the-art review. Sustainability. 2024;16(2):670. doi:10.3390/su16020670.

3. Gharbage I, Benmahiddine F, Sebaibi N. Mechanical, thermal and hydric properties of compressed earth blocks: a review. J Build Eng. 2025;104:112387. doi:10.1016/j.jobe.2025.112387.

4. Touati K, Le Guern M, El Mendili Y, Azil A, Streiff F, Carfrae J, et al. Earthen-based building: in-situ drying kinetics and shrinkage. Constr Build Mater. 2023;369:130544. doi:10.1016/j.conbuildmat.2023.130544.

5. Walter L, Medjigbodo G, Estevez Y, Linguet L, Nait-Rabah O. Tannin with sodium carbonate: a single additive for poured earth concrete with tropical soils. Results Eng. 2025;25:103981. doi:10.1016/j.rineng.2025.103981.

6. Yang F, Zhao Z, Jia Z, Niu W, Liu Y, Song F, et al. Study on the mechanical properties and microscopic mechanism of xanthan gum improved red clay. Sci Rep. 2025;15(1):31842. doi:10.1038/s41598-025-16425-3.

7. Rajabi AM, Ardakani SB. Effects of natural-zeolite additive on mechanical and physicochemical properties of clayey soils. J Mater Civ Eng. 2020;32(10):04020306. doi:10.1061/(asce)mt.1943-5533.0003336.

8. Hwang HY, Kwon YH, Hong SG, Kang SH. Comparative study of effects of natural organic additives and cellulose ether on properties of lime-clay mortars. J Build Eng. 2022;48(2):103972. doi:10.1016/j.jobe.2021.103972.

9. Valipour M, Shourijeh PT, Mohammadinia A. Application of recycled tire polymer fibers and glass fibers for clay reinforcement. Transp Geotech. 2021;27(3):100474. doi:10.1016/j.trgeo.2020.100474.

10. Arabani M, Shalchian MM, Majd Rahimabadi M. Use of wheat fiber and nanobentonite to stabilize clay subgrades. Results Eng. 2024;24(7):102931. doi:10.1016/j.rineng.2024.102931.

11. Lin J, Wu D, Jia J, Yan J, Cai L. Changes in the basic structure and strength deterioration of clay minerals with different hydration degrees. Clay Miner. 2023;58(3):324–33. doi:10.1180/clm.2023.29.

12. Amer I, Kohail M, El-Feky MS, Rashad A, Khalaf MA. A review on alkali-activated slag concrete. Ain Shams Eng J. 2021;12(2):1475–99. doi:10.1016/j.asej.2020.12.003.

13. Marvila MT, de Azevedo ARG, de Oliveira LB, de Castro Xavier G, Vieira CMF. Mechanical, physical and durability properties of activated alkali cement based on blast furnace slag as a function of %Na₂O. Case Stud Constr Mater. 2021;15:e00723. doi:10.1016/j.cscm.2021.e00723.

14. Cartwright C, Rajabipour F, Radlińska A. Shrinkage characteristics of alkali-activated slag cements. J Mater Civ Eng. 2015;27(7):B4014007. doi:10.1061/(asce)mt.1943-5533.0001058.

15. Chen JJ, Ng PL, Xu L, Kwan AKH. Use of nano-silica sol in concrete: performance and influence mechanisms. Constr Build Mater. 2024;411(4):134582. doi:10.1016/j.conbuildmat.2023.134582.

16. ASTM C191-21. Standard test methods for time of setting of hydraulic cement by Vicat Needle. West Conshohocken, PA, USA: ASTM International; 2021.

17. ASTM C1437-20. Standard test method for flow of hydraulic cement mortar. West Conshohocken, PA, USA: ASTM International; 2020.

18. ASTM C1702-24. Standard test method for measurement of heat of hydration of hydraulic cementitious materials using isothermal conduction calorimetry. West Conshohocken, PA, USA: ASTM International; 2024.

19. ASTM C109/C109M-24. Standard test method for compressive strength of hydraulic cement mortars (Using 50 mm [2-in.] Cube Specimens). West Conshohocken, PA, USA: ASTM International; 2024.

20. ASTM C1698-19. Standard test method for autogenous strain of cement paste and mortar. West Conshohocken, PA, USA: ASTM International; 2019.

21. ASTM C157/C157M-24. Standard test method for length change of hardened hydraulic-cement mortar and concrete. West Conshohocken, PA, USA: ASTM International; 2024.

22. Wang W, Wang B. Study on the influence of nano-silica substitution of reactive Si on the properties and hydration process of alkali-activated cementitious materials paste. Constr Build Mater. 2024;443:137759. doi:10.1016/j.conbuildmat.2024.137759.

23. Peng Y, Ma K, Long G, Xie Y. Influence of nano-SiO₂, nano-CaCO₃ and nano-Al₂O₃ on rheological properties of cement-fly ash paste. Materials. 2019;12(16):2598. doi:10.3390/ma12162598.

24. Liu H, Li Q, Su D, Yue G, Wang L. Study on the influence of nanosilica sol on the hydration process of different kinds of cement and mortar properties. Materials. 2021;14(13):3653. doi:10.3390/ma14133653.

25. Overmann S, Eggimann M, Vollpracht A, Matschei T. Impact of clay reactivity on the hydration of calcined clay limestone cements. Constr Build Mater. 2024;449:138455. doi:10.1016/j.conbuildmat.2024.138455.

26. De Filippis U, Prud’homme E, Meille S. Raw earth stabilised by alkaline activation of slag: effect of clay on slag hydration. Materialia. 2024;36(2):102143. doi:10.1016/j.mtla.2024.102143.

27. Honty M, De Craen M, Wang L, Madejová J, Czímerová A, Pentrák M, et al. The effect of high pH alkaline solutions on the mineral stability of the Boom Clay–Batch experiments at 60°C. Appl Geochem. 2010;25(6):825–40. doi:10.1016/j.apgeochem.2010.03.002.

28. Xie J, Chen P, Li J, Xu Y, Fang Y, Wang A, et al. Directly upcycling copper mining wastewater into a source of mixing water for the preparation of alkali-activated slag materials. Process Saf Environ Prot. 2022;168(12–13):362–71. doi:10.1016/j.psep.2022.10.011.

29. Jeong Y, Park H, Jun Y, Jeong JH, Oh JE. Influence of slag characteristics on strength development and reaction products in a CaO-activated slag system. Cem Concr Compos. 2016;72(3):155–67. doi:10.1016/j.cemconcomp.2016.06.005.

30. Bian Z, Jin G, Ji T. Effect of combined activator of Ca(OH)₂ and Na₂CO₃ on workability and compressive strength of alkali-activated ferronickel slag system. Cem Concr Compos. 2021;123(10):104179. doi:10.1016/j.cemconcomp.2021.104179.

31. Scrivener K, Lothenbach B, Snellings R, editors. A practical guide to microstructural analysis of cementitious materials. Boca Raton, FL, USA: CRC Press; 2016.

32. Wang F, Chen P, Li X, Zhu B. Effect of colloidal silica on the hydration behavior of calcium aluminate cement. Materials. 2018;11(10):1849. doi:10.3390/ma11101849.

33. Angulo-Ramírez DE, Mejía de Gutiérrez R, Puertas F. Alkali-activated Portland blast-furnace slag cement: mechanical properties and hydration. Constr Build Mater. 2017;140:119–28. doi:10.1016/j.conbuildmat.2017.02.092.

34. Zhang H, Chai W, Cao Y. Flotation separation of quartz from gypsum using benzyl quaternary ammonium salt as collector. Appl Surf Sci. 2022;576(2):151834. doi:10.1016/j.apsusc.2021.151834.

35. Sun X, Liu J, Qiu J, Wu P, Zhao Y. Alkali activation of blast furnace slag using a carbonate-calcium carbide residue alkaline mixture to prepare cemented paste backfill. Constr Build Mater. 2022;320(10):126234. doi:10.1016/j.conbuildmat.2021.126234.

36. García Lodeiro I, Macphee DE, Palomo A, Fernández-Jiménez A. Effect of alkalis on fresh C–S–H gels. FTIR analysis. Cem Concr Res. 2009;39(3):147–53. doi:10.1016/j.cemconres.2009.01.003.

37. He J, Bai W, Zheng W, He J, Sang G. Influence of hydrated lime on mechanical and shrinkage properties of alkali-activated slag cement. Constr Build Mater. 2021;289(2):123201. doi:10.1016/j.conbuildmat.2021.123201.

38. Chen P, Tian F, Zhang J, Li Y, Wei Y. Effect of nano-silica on mechanical properties and shrinkage of alkali-activated slag cementitious material. Dev Built Environ. 2024;19(9):100525. doi:10.1016/j.dibe.2024.100525.

39. Hou P, Wang X, Zhao P, Wang K, Kawashima S, Li Q, et al. Physicochemical effects of nanosilica on C3A/C3S hydration. J Am Ceram Soc. 2020;103(11):6505–18. doi:10.1111/jace.17364.

40. Chen Z, Chen P, Li S, Shen X, Fang J, Gu Z, et al. Enhancing the performance of NaOH-activated slag using waste green tea extract as a multi-function admixture. Case Stud Constr Mater. 2024;21(1):e03605. doi:10.1016/j.cscm.2024.e03605.

41. Huang X, Xin C, Li JS, Wang P, Liao S, Poon CS, et al. Using hazardous barium slag as a novel admixture for alkali activated slag cement. Cem Concr Compos. 2022;125(5):104332. doi:10.1016/j.cemconcomp.2021.104332.

42. Lu J, Jiang J, Lu Z, Li J, Shi Y. Preparation and properties of nanopore-rich cement-based porous materials based on colloidal silica sol. Constr Build Mater. 2021;299(11):123966. doi:10.1016/j.conbuildmat.2021.123966.

43. Rahoui H, Maruyama I, Vandamme M, Pereira JM, Mosquet M. Impact of alkalis and shrinkage-reducing admixtures on hydration and pore structure of hardened cement pastes. Cem Concr Res. 2024;184(2):107620. doi:10.1016/j.cemconres.2024.107620.

44. Li Z, Chen Y, Provis JL, Cizer Ö, Ye G. Autogenous shrinkage of alkali-activated slag: a critical review. Cem Concr Res. 2023;172:107244. doi:10.1016/j.cemconres.2023.107244.

45. Geng Z, Zhang Y, Zhou Y, Duan J, Yu Z. Effect of nano-SiO₂ on the hydration, microstructure, and mechanical performances of solid waste-based cementitious materials. Materials. 2025;18(11):2636. doi:10.3390/ma18112636.

46. Nair S, Little D. Water as the key to expansion of ettringite in cementitious materials. Transp Res Rec J Transp Res Board. 2009;2104(1):55–62. doi:10.3141/2104-06.

47. Fang G, Bahrami H, Zhang M. Mechanisms of autogenous shrinkage of alkali-activated fly ash-slag pastes cured at ambient temperature within 24 h. Constr Build Mater. 2018;171:377–87. doi:10.1016/j.conbuildmat.2018.03.155.

Cite This Article

APA Style

Liu, Y., Luo, W., Wang, L., Xu, Q., Wu, W. et al. (2026). Effect of silica sol on mechanical and shrinkage properties of alkali-activated slag-bonded clay. ZKG International, 118–130. https://doi.org/10.32604/zkg.2026.079210

Vancouver Style

Liu Y, Luo W, Wang L, Xu Q, Wu W, Chen P. Effect of silica sol on mechanical and shrinkage properties of alkali-activated slag-bonded clay. ZKG Int.. 2026;:118–130. https://doi.org/10.32604/zkg.2026.079210

IEEE Style

Y. Liu, W. Luo, L. Wang, Q. Xu, W. Wu, and P. Chen, “Effect of silica sol on mechanical and shrinkage properties of alkali-activated slag-bonded clay,” ZKG Int., pp. 118–130, 2026. https://doi.org/10.32604/zkg.2026.079210

Effect of silica sol on mechanical and shrinkage properties of alkali-activated slag-bonded clay

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