Impact of crushed sand and lime on clayey soil for pavement sub- grade

Abstract. Black cotton soil, a common inorganic clay in India, covers around 20% of the nation, primarily in the central and western areas. This soil type presents considerable issues for road building because to its shrinkage and swelling properties, which result in fissures and uneven settling. Replacing the soil is impractical, thus soil stability is essential. This study looks at a unique way for improving soil engineering qualities by employing crushed sand and lime as stabilizers. The study examines various blends of black cotton soil with crushed sand and lime, including a control sample and three blends: BLC-1 (2% lime, 5% crushed sand, 93% soil), BLC-2 (4% lime, 10% crushed sand, 86% soil), and BLC-3 (6% lime, 15% crushed sand, 79% soil). Extensive laboratory tests, including Atterberg's limit tests, specific gravity, compaction tests and free swell index test, were conducted. The results show that the addition of crushed sand and lime significantly enhances the soil's properties. BLC-3, in particular, demonstrated the most substantial improvements, with increased maximum dry density, reduced free swell index and enhanced shear strength. Microstructural analysis confirmed a more uniform mineral distribution, contributing to better stability and bearing capacity.