Strength Enhancement of Silty Sand Soil Subgrade of Highway Pavement Using Lime and Fines from Demolished Concrete Wastes

摘要

The highway pavement quality and lifetime depend on its different layers such as subgrade, sub-base and base courses. It is of great importance for subgrade soil layer to have the excellent properties as it is the one to lower or increase the project cost. This paper discusses the utilization of lime and fines from concrete waste to enhance the strength of silty sand soil. California Bearing Ratio (CBR) and shear strength were evaluated. The content such as 0%, 2%, 4%, 6%, 8% and 10% were used. The CBR and shear strength of soil increased with the increase of lime or concrete content. The optimum lime and concrete content which maximized CBR were 6% and 8% respectively. The optimum lime content which gave the maximum shear strength was 8%. However there was no optimum content of concrete waste which maximized shear strength. Finally, it has been noticed that stabilisation of the silty sand subgrade with the fines from the concrete demolished waste has improved both the fatigue cracking and rutting resistance capacity of the pavement structure more than lime stabilised and non-stabilised subgrade.