Engineering behavior of cement-treated stiff clay subjected to freezing/thawing cycles

Abstract

Deep soil mixing (DSM) with cement has been adopted to enhance soft ground and stabilize problematic soils worldwide. The literature is limited to DSM-treated soft soils with low cement contents, temperate curing conditions, short-term stability, and compressive properties. Due to the increased applications of DSM in cold regions, the study on the mechanical behavior of cemented soils (soilcrete) with high cement content under freezing/thawing (F/T) conditions has become important. In the present study, cylindrical specimens formed by mixing Edmonton stiff clay with high ordinary Portland cement contents (over 20%) were prepared in the lab to examine the mechanical behavior of soilcrete under unexposed and F/T exposed conditions. Unconfined compression and tensile tests were performed to assess changes in the mechanical properties of specimens cured for 1 to 300 days after 1 to 20 F/T cycles at freezing temperatures from −2 to −20 °C. Test results showed that the compressive and tensile strength of soilcrete increased with curing age and decreased significantly with more F/T cycles. Additionally, the mechanical strength loss in the −5 to −10 °C range was more significant than in the −2 to −5 °C range, indicating that the lower temperature caused more severe damage to the samples. Although the mass loss was <5% for most samples, it increased with more F/T cycles and the declining temperature, indicating that the mass loss was able to reflect the impact of F/T cycles.