Anti-disintegration property of red soil treated with building gypsum powder

Abstract

Red soil exhibits a tendency to soften and disintegrate upon exposure to water, posing significant geological hazards and engineering challenges. In the present study, building gypsum powder (BGP) was employed as a modifier to systematically investigate its influence on the resistance to disintegration of red soil under the influence of various alkaline admixtures. Utilizing a custom-built dry-wet cycle disintegration tester, in conjunction with microscopic analysis techniques including scanning electron microscopy (SEM), X-ray diffraction (XRD), XRF (X-ray Fluorescence) and mercury intrusion porosimetry (MIP), the enhancement mechanism of BGP on the microstructure of red soil was thoroughly investigated. The findings indicate that an increase in the dosage of BGP markedly enhances the resistance to disintegration of red soil, particularly when the dosage surpasses 5 %. Under the influence of various admixtures, BGP-modified red soil undergoes chemical processes, including ion exchange, crystallization, and volcanic ash reaction, leading to a significant reduction in porosity, an increase in density, and a marked improvement in the water stability of red soil. The dry-wet cycle test provided further confirmation that the admixture markedly improved the water stability of BGP-modified red soil. Furthermore, the quantitative relationship between the microstructural parameters of the modified red soil and its disintegration properties was established through the application of grey correlation analysis and fractal theory, elucidating the crucial role of pore perimeter and area in the resistance to disintegration of red soil. This research endeavors to establish a scientific foundation for the prevention and mitigation of debris flows, landslides, and other disasters in red soil regions, and to propose novel strategies for the selection of geotechnical enhancement materials.