Characterization of nano-SiO2 cemented soil under the coupled effects of dry-wet cycles and chlorination

Abstract

In contrast to cemented soils in terrestrial natural environments, cemented soils in littoral and marine geotechnical engineering face numerous difficulties. In coastal and marine geotechnical engineering, cemented soils are frequently degraded by ion erosion, tidal scouring, and temperature variations. Long-term marine environments present numerous challenges for cemented soil foundation projects. In marine geotechnical engineering, addressing and enhancing these degradation issues has become a crucial topic. To address this engineering problem, Nano-SiO2 is added to cement-stabilized soils to enhance their engineering performance. To investigate the mechanical effects and erosion mechanisms of Nano-SiO2 cemented soil subjected to chloride ion erosion and tidal alternation scouring, laboratory experiments, including immersion erosion tests with sodium chloride solution and dry-wet cycle tests, were designed. On specimens subjected to dry-wet cycles after chloride ion erosion at varying concentrations, unconfined compressive strength tests (UCS), X-ray diffraction (XRD) experiments, and scanning electron microscopy (SEM) were performed. The objective was to investigate the impact of chloride ions and Nano-SiO2 on the microstructure and strength of cemented soil. Adding 2.5% Nano-SiO2 can promote cement hydration reactions while preventing the entry of chloride ions into the cemented soil, thereby increasing the density and compressive strength of the cement.