Medium-Scale Experimental Study on Moisture Control of Subgrade

The moisture content of subgrade has a significant effect on the pavement performance, and many highway pavement distresses have resulted from the high moisture content of subgrade in humid zone or seasonally frozen zone. So there is a practical need for efficient moisture control methods for in-service subgrades. In this paper, drainage performances of compacted soils with given water content were investigated by medium-scale experiments, which were designed as natural draining and electro-osmosis dewatering, and then the relationships between drainage performances and soil types, layers, and time were analyzed. It is shown that the sand and silt have much better drainage performance than clay in natural draining, as the water contents decrease by 4.28%, 2.92% and 0.54%, respectively. However, the drainage performances of the two clays are significantly enhanced by electro-osmosis, and the water contents reduce 3.47% and 3.78% by the direct-current power supply of 24V. Moreover, the increase in the voltage value improves the drainage performance, which can be interpreted in terms of soil water potential.