Strength Properties of Cement-Treated Lean Clay Cured at Constant and Changing Temperature

Environmental temperature is usually variable in the field and can significantly affect the mechanical behavior of cemented soil. However, how the initially low-temperature curing affects the strength behavior of cemented lean clay is still pending. To identify the influence of changing temperature on the strength behavior of cemented lean clay, a series of unconfined compression strength (UCS) tests were carried out in this research. Based on test results, an overall detrimental influence on the unconfined compressive strength (qu) was found due to low-temperature curing. Compared with cemented lean clay cured at a constant low temperature, an increase in qu was observed when the curing temperature rose again to 20°C, and the recovery in qu depends mainly upon the initial low-temperature curing time. The improvement in cement hydration was the main source in strength gain for cemented lean clay cured initially at 5°C/10°C. However, for cemented lean clay once cured at 0°C, the formation and thawing of pore ice damaged the soil structure and resulted in permanent damage to the development of strength. Moreover, the failure strain εf and secant modulus E50 were consistent well with qu when the temperature was not less than 5°C. For cemented lean clay used in this study, a curing temperature range of 5°C–20°C would guarantee adequate qu.