Strength Behaviour of Expansive Subgrade Soil Stabilized with Coronus Material

Expansive subgrade soil needs to be re-engineered to enhance the load-bearing capacity as it lacks the capacity to sustain traffic and pavement load. Although various chemical modification techniques have proven to be effective for stabilization, they are expensive and unsustainable. Coronus aggregate material is an uplifted coralline deposit abundantly available in the Pacific. The current study focuses on the strength behavior of fine-grained soil notably clayey soil when blended with coronus material as a potential alternative to the usual soil stabilization methods employed in the construction industry. To successfully stabilize the clayey soil sample with the coronus material, the particle size distribution, coefficient of uniformity, and curvature of the clayey soil sample and coronus material were determined. The results indicate that the coronus material is well-graded. The consistency of the soil sample was determined using the four-point Casagrande method for Atterberg limits i.e, the liquid limit, plastic limit, and shrinkage limit of the clayey soil. The load-bearing capacity of the clayey soil stabilized with coronus material was determined using standard compaction tests to calculate the maximum dry density and optimum moisture content of clay before and after blending with 10% increments of coronus material. The California Bearing Ratio (CBR) test results of all the samples were determined using standard CBR laboratory tests. It has been observed that the addition of coronus material has improved the load-bearing capacity of clayey soil. Hence, it is recommended that, wherever possible, coronus material be utilized as a stabilizing agent to improve the geotechnical properties of expansive subgrade soil.