Improvement of Pavement Subgrade Soil using Millet Husk Ash for Rural Roads

This paper focuses on the improvement of subgrade soil by using Millet Husk Ash (MHA). MHA is a commonly available material found in a significant quantity as India is the largest producer of millet in the entire world. The MHA was mixed in soil by partially replacing the soil by weight in 0%,2.5%,5%,7.5%,10%,12.5% and 15%. The soil in its natural state was in the form of intermediate plastic clay whose dry density got reduced and the optimum moisture content got increased after stabilization. The CBR and UCS values increased initially but showed a decrease after a certain point. The sudden transition from increasing values to decreasing values marks a peak point showing the optimum content of MHA. The optimum content of the ash was found to be 10%. A significant increase in the values of UCS and CBR was also observed.