文献类型：期刊文献

英文题名：Effects of alkali contamination on mechanical properties and microstructure of red clay

作者：Wang, Lianrui Chen, Jun Liu, Dongdong Lan, Yujie

第一作者：Wang, Lianrui

通信作者：Chen, J[1];Chen, J[2]

机构：[1]Guizhou Univ, Coll Resources & Environm Engn, Guiyang 550025, Peoples R China;[2]Guizhou Inst Water Resources Sci, Guiyang 550002, Peoples R China;[3]Guizhou Inst Technol, Dept Pathol, Guiyang 550007, Peoples R China

第一机构：Guizhou Univ, Coll Resources & Environm Engn, Guiyang 550025, Peoples R China

通信机构：corresponding author), Guizhou Univ, Coll Resources & Environm Engn, Guiyang 550025, Peoples R China;corresponding author), Guizhou Inst Technol, Dept Pathol, Guiyang 550007, Peoples R China.|贵州理工学院;

年份：2026

卷号：16

期号：1

外文期刊名：SCIENTIFIC REPORTS

收录：;WOS:【SCI-EXPANDED(收录号:WOS:001694160700020)】；

基金：This research was supported by the Guizhou Provincial Science and Technology Department, China (Z113278; No.[2019]1142).

语种：英文

外文关键词：Red clay; Alkali contamination; Mechanical properties; Microstructure; Concentration effect

摘要：Alkaline environments significantly affect the engineering properties of red clay. Although the effects of alkali contamination on the microstructure and mechanical characteristics of cohesive soils have been extensively studied, systematic research focusing on red clay remains limited. This study employed NaOH solution to simulate alkali contamination of red clay. By utilizing unconsolidated undrained (UU) triaxial shear tests, mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), laser particle size analysis (LPSA), and X-ray diffraction (XRD), this work systematically investigated the influence of different alkali concentrations on the mechanical properties and microstructure of red clay. The results indicate a distinct threshold effect of alkali concentration on red clay behavior, with the existence of a most unfavorable concentration (3.5%) and an optimal concentration (14%). At the 3.5% concentration, destructive dissolution was dominant, in which mineral dissolution led to particle refinement, surface smoothing, and an increase in the proportion of large pores, resulting in a significant reduction in soil strength. At 14% concentration, reconstructive cementation became prevalent. XRD analysis confirmed the formation of new crystalline phases (sodium aluminosilicate), indicating the occurrence of geopolymerization. The newly formed cementitious materials effectively bonded soil particles and filled pores, thereby enhancing shear strength, although their brittle nature resulted in strain softening during shearing. At excessively high concentrations (e.g., 21%), structural degradation and strength reduction were again observed. This research reveals the dynamic evolution of the "dissolution-cementation" competition mechanism in red clay under different concentrations of alkali contamination, providing a theoretical basis for preventing alkali contamination in red clay foundations and for soil reinforcement techniques based on alkali activation principles.