Experimental Study on Strength and Microstructure of Cemented Soil with Different Suctions

The use of cement as curing agent to increase the strength of soft ground and reduce the deformation of soft soils has been widely adopted in soft soil engineering. The cemented soil is eventually exposed to the air, and becomes unsaturated in natural environments. This paper presents experimental studies, including suction control using a vapor equilibrium technique, unconfined compression strength tests, scanning electron microscope analysis, and mercury intrusion porosimetry tests, to investigate the influence of suction, cement content, and dry density on the strength and microstructure of unsaturated cemented soils. The experimental results show that unconfined compressive strength increases with increases in suction at the same dry density and the same cement content. The results also indicate that unconfined compressive strength decreases with decreases in dry density at the same cement content and the same suction. The microstructure study shows that, although strength increases with an increase in cement content, the hydration products of cement are seldom observed under high suction. The distribution of internal pores (micropores) in samples with different dry densities is almost the same, but distinct differences in the distribution of pores in aggregates (macropores) are observed.