Study on the Improvement of Properties of Expansive Soil Using Seashell Powder

Due to rapid urbanization, it is necessary to utilize the site which is problematic in nature. One of the most problematic soils is expansive soil, and it possesses an excessive swelling and shrinking property on temperature variation which poses a significant danger to carrying out construction works. In order to make the soil suitable for construction, many ground improvement techniques are used. The most commonly used ground improvement technique is soil stabilization. Soil stabilization is the addition of admixture to the soil for improving its strength characteristics for which the admixtures generally used are lime, cement, fly ash etc. In this study, seashell powder is being used as an additive. Seashells are waste products produced from the fishery industry. It acts as a binding material for soil, thus stabilizing the soil. Added to it, it has a high calcium content. In this investigation, varied amounts of seashell powder (6, 8, 10, 12, and 15%) were mixed to untreated expansive soil. The compaction, strength, and swell characteristics of the soil were then determined for different curing periods (3, 7, 14, and 28 days). According to the IS standards, the standard Proctor compaction tests, unconfined compression tests, and free swell tests were used to determine the findings for the soil's compaction, strength, and swell properties. Based upon analyzing the results from the tests, it is found that the strength of the soil increases significantly compared to the untreated soil on increasing the percentage of seashell powder. The maximum strength of the soil is attained on adding 12% admixture under 28-day curing period. Compared to the initial strength of the untreated soil, the soil’s strength rose by 88.87%. Thus, seashell powder acts as a cost-effective admixture especially for expansive soil.