A Comparative Study on Fly Ash and Bagasse Ash Using as a Sub-Grade Material

Expansive soil is prone to large volume changes (swelling and shrinking) that are directly related to changes in moisture. So the low bearing strength and high compressibility behavior of soil can cause severe damage to subgrade. In this research the enumeration of the strength of soil by adding different types of ground improvement materials like as fly ash and bagasse ash in order to overcome such type of damages. The California Bearing Ratio (CBR) test to determine the stability of subgrade soil by adding fly-ash and bagasse ash separately at different percentages. The objective of this paper is to study the combined effects of Fly Ash and Bagasse Ash on Maximum Dry Density (MDD), Optimum Moisture Content (OMC), Soaked CBR and Swelling pressure of expansive soil. The effects of molding water content and compaction delay, on soaked CBR of both Ashes stabilized expansive soil have also been studied. CBR tests were performed with fly-ash and bagasse ash separately at different percentage variations with the increment of 2.5% by weight in order to find out which one is most suitable for stabilization of subgrade material. The results show that initially the optimum moisture content (OMC) of soil is 13.5% and for addition of fly ash and bagasse ash separately up to 12.5% it has become in increase up to 19.1% and 15.26% respectively. Initially the CBR value of soil is 6.63%. For addition of bagasse ash up to 10% the CBR value of soil has become in increase up to 13.87% and after then for addition of 12.5% bagasse ash it has become in decrease 13.42%. For fly ash the CBR value for 10% is 15.11%, which is larger than the bagasse ash.