Strength damage analysis on cement-and-fly ash-treated organic soils subjected to freeze–thaw cycles

Abstract

ABSTRACT Organic soil is usually required to be improved/treated before engineering construction, especially in cold regions due to deterioration introduced by freeze–thaw cycle. In this study, cement-and-fly ash is adopted as agents to stabilise the organic soil. A photogrammetric method is proposed to accurately reconstruct the surface of these cement-and-fly ash-treated organic soils and measure the volume before and after freeze–thaw cycles (F–T-C). Meantime, unconfined compression (U-C) test was performed to evaluate the performance of these specimens after different numbers of F–T-C, and the influence of organic content on soil behaviour was also investigated. These results indicated that an increase in the cement content enhanced the resistance of the organic soils against volume change before and after F–T-C. A proper adoption of cement-and-fly ash significantly improves the unconfined compression strength (UCS) of organic soils subjected to different numbers of F–T-C. The strength of treated organic soil continuously decreased with increasing content of organic. A model was also established to predict soil stress–strain curves with consideration of the number of F–T-C and volumetric changes after the F–T-C.