Assessing the Effectiveness of Stabilizing Expansive In-Situ Subgrade Soils on Road Projects in Uganda Using Bagasse Ash

Abstract

Unsuitable soils for road construction can be improved by a process called stabilization. This is the addition of additives to the soil in order to improve its engineering properties. The most common means of stabilization is by use of lime, cement or fly ash. These means have proved to be expensive and are not environmentally friendly. These concerns have led to the use of unconventional stabilizers that are cheaper and have minimal effect on the environment, such as enzymes and Bagasse Ash. This study examined the use of Bagasse Ash as a stabilizing agent and was aimed at determining the effectiveness and suitability of using it in improving the properties of Expansive In-Situ Subgrade Soils Representative samples were extracted and taken to the laboratory. The research was mainly based on laboratory testing of plasticity and strength parameters of the soils. Results show that indeed the bagasse ash alters the properties of the expansive soil positively. Bagasse ash significantly reduced the Plasticity Index by over 45% on average and the California Bearing Ratio increased by over 105%. When compared to the minimum requirements of a subgrade material, the strength results were achieved and are therefore recommended for use on road projects with subgrade soils of inferior properties.