Stabilizing black cotton soil in subgrade with municipal solid waste incineration ash for lowering greenhouse gas emission: A review

Abstract

The construction of bituminous pavement causes greenhouse gas emissions which can be reduced significantly by using municipal solid waste incineration (MSWI) ash in the subgrade. The present study is the review of work carried out by various researchers on the improvement of engineering properties of expansive soils, namely black cotton soil (BCS), after the addition of MSWI ash to the soil in varying proportions. The study findings indicate that the optimum content of MSWI ash to be added to expansive soils for improvement in strength characteristics varies between 10% and 30%, with the best results at 25% of MSWI ash proportion. This content of MSWI ash increases the unconfined compressive strength (UCS) of expansive black cotton soil from 28.8 kPa to 53.4 kPa and an increase in CBR value from 3.38% to 9.38%. Therefore, the review suggests using MSWI ash, keeping in view the enormous increase in volumes of municipal solid waste (MSW) due to fast urbanization in the country. Most of the past studies on soil stabilization through ashes are based on ashes of thermal power projects. Still, the present research focuses on using MSWI ash for the dual purpose of stabilization of black cotton soil to be used as subgrade material and to minimize greenhouse emissions. This is the novelty of the present study.