Strength and Durability Properties of Marginal Lateritic Soil-Bagasse Ash Based Geopolymer with Cement Supplements as Pavement Subbase Materials

This study investigates the strength and durability of bagasse ash (BA) and cement (C) geopolymer-stabilized marginal lateritic soil (MLS) when used as a subbase material. The effect of binder (B) content, liquid alkaline content, sodium silicate (NS):sodium hydroxide (NH) ratio, NH concentration, BA:C ratio, curing time, and wetting and drying cycles number (N) on the compaction curve, unconfined compressive strength (UCS), water absorption, and weight loss were evaluated. The samples' maximum dry unit weight and optimal liquid alkaline content ranged from 18 to 18.7 kN/m3 and 13% to 21%, respectively. The highest 7-day UCS value was found at ratios of 55MLS:45B, 100BA:0C, 80NS:20NH, and 5 M NH, which offered a 7-day UCS value of 7.9 MPa. In addition, all mixtures met the requirement to be used as subbase materials. The UCS values of the BA-C geopolymer stabilized MLS sample decreased as the N increased for all ingredients, which was associated with increased water absorption and weight loss. The UCS values exceeded 689 kPa (strength requirement for subbase material) N = 9, except for those with a 100BA:0C ratio. This study can use BA previously intended for the landfill as a sustainable binder for pavement subbase material.