Evolution of waterproof performance,mechanical properties,and microstructure in hydrophobically-modified geopolymer concrete during dry-wet cycles  

作　　者：Dongming YAN Yilu QIU Rongfeng GAO Shikun CHEN Yi LIU Shengqian RUAN 

机构地区：[1]College of Civil Engineering and Architecture,Zhejiang University,Hangzhou,310058,China [2]School of Materials Science and Engineering,Zhejiang University,Hangzhou,310058,China

出　　处：《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》2025年第3期194-211,共18页浙江大学学报(英文版)A辑(应用物理与工程)

基　　金：supported by the National Natural Science Foundation of China(Nos.52101328 and 52171277);the National Key Research and Development Program of China(No.2022YFE0109200);the Foundation of the Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(No.2022SZ-TD006);the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(CPSF)(No.GZB20230653)。

摘　　要：The waterproof performance,mechanical properties,chemical composition,microstructure,and pore structure of hydrophobically-modified geopolymer concrete are investigated before and after dry-wet cycles,to determine the long-term feasibility of using hydrophobically-modified geopolymer concrete in wet environments.We use two types of organic modifying agents:polydimethylsiloxane(PDMS)and sodium methyl siliconate(SMS).The experimental results show that incorporating 2%–6%PDMS or 5%–15%SMS can make the concrete hydrophobic,with water absorption and chloride transport rates decreasing by up to 94.3%.We also analyze the bonding modes of organic molecules and geopolymer gels,as well as their evolution mechanisms during dry-wet cycles.PDMS-modified geopolymer concrete is found to exhibit long-term waterproof performance that is not weakened by dry-wet cycles.This is attributed to the robust combination of organic components and the geopolymer gel skeleton formed through phase cross-linking.Meanwhile,PDMS-modified geopolymer concrete’s hydrophobicity,strength,and microstructure are essentially unaffected.In contrast,SMS-modified geopolymer concrete shows higher water sensitivity,although it does maintain efficient waterproof performance.Due to relatively low binding energy,the dry-wet cycles may lead to the detachment of some SMS molecules from the gel network,which results in a decrease of 18.6%in compressive strength and an increase of 37.6%in total porosity.This work confirms the utility of hydrophobically-modified geopolymer concrete as a building material for long-term service in wet environments,for instance,areas with frequent precipitation,or splash and tidal zones.

关 键 词：Geopolymer concrete Hydrophobic modification Waterproof performance Mechanical property Microstructure analysis 

分 类 号：TU528[建筑科学—建筑技术科学]