Effect of the cement on the swell and CBR behavior of silty soil = Ảnh hưởng của xi măng đến ứng xử trương nở và giá trị CBR của đất bùn lòng sông

Abstract

Using riverbed soil for road embankments instead of sand would be beneficial. However, the riverbed soil is weak, with a low capacity and a high potential to swell when its moisture increases. Therefore, cement is used as a reinforcement material to improve the soil capacity and its swell. In this research, cement with ratios of 3%, 5%, and 10% was used to mix with the riverbed soil. The result showed that the percentage of swell in cement-soil samples was significantly lower than that of soil samples (1.78% of the samples with 10% cement compared to 4.4% of soil specimens). Besides, the swelling velocity of cement-treated soil was considerably higher than that of the soil, and the soil swelling of the former reached equilibrium faster than that of the latter. Additionally, the CBR of soil was significantly improved when reinforced with cement, increasing to 3.78 times with 10% cement. The results indicated that the largest increase in CBR value occurred when the cement content increased from 3% to 5%. The rate of increase in CBR decreased when the cement content increased from 5% to 10%. The swelling and soil strength are improved because of the pozzolanic and hydration processes that create the bonding in cement-treated soil.