Influence of Curing Stress and Curing Time on Unconfined Compressive Strength Behaviour of Cemented Clay

Abstract

In recent ground improvement techniques to strengthen the weak soils in order to increase the strength characteristics and stiffness of different types of soils, cement stabilisation has shown to be very effective. In cement stabilisation, curing stress and curing time are two important factors. Since previous researchers have mainly focused on importance of the curing time, the present study emphasises on the combined effect of curing stress and curing time. The aim of present study is to examine the effect of curing time on unconfined compressive strength (UCS) of virgin clayey soil treated with cement under predefined curing stress of 5 kPa. Laboratory test including Atterberg limits, light weight compaction test and UCS test were conducted. The UCS tests were performed on clayey soil (CH) with the different percentages of cement (i.e. 8, 10 and 12%) for the curing period of 0, 3, 7, 14, 28 and 56 days. The curing stress of 5 kPa is being applied along with curing time to check the combined effect of both curing time and curing stress. The results show that the curing time and the curing stress have a significant effect on UCS. The UCS value increases with increasing cement content from 8 to 10% but decreases for further increment in cement content (i.e. from 10 to 12%). The 10% cement content is found to be the optimum. UCS values increases with curing stress and having around 10–15% high value compared to the curing time condition. The increase in UCS is attributed due to the reduced pore spaces and increased confinement due to the curing stress. This study concluded that applying curing stress leads to have incremental impact on the strength of soil and being very helpful for attaining higher strengths in early days.