Changes in thermal conductivity, suction and microstructure of a compacted lime-treated silty soil during curing

• Pozzolanic reaction decreases the modal sizes of small and large pores.
• The produced cementitious compounds decrease soil thermal conductivity.
• The produced cementitious compounds increase soil suction.

An experimental study was conducted to investigate changes of thermal conductivity, suction and microstructure of a lime-treated silty soil during curing. The soil samples were prepared with 2% lime and compacted dry (17%) and wet (22%) of optimum. The thermal conductivity, total suction and pore size distribution were determined at various curing times. Results show that the thermal conductivity of samples compacted on the dry side decreases slightly with curing time, while the curing time effect on the samples compacted on the wet side is insignificant. The total suction generally increases with curing time even though the soil water content was kept constant. The pore size distribution characteristics are mainly related to its moulding water content. As the samples are compacted on the dry side, the pore size distribution shows typical bi-modal characteristics, with a population of macro-pores and a population of micro-pores. By contrast, as the samples are compacted on the wet side, the pore size distribution shows typical uni-modal characteristics. It is found that the modal size of both the large and small pores decrease with curing time.