Stabilization of Black Cotton Soil by Using RBI Grade-81: A Review

Due to rapid abrupt change in behavior of black cotton (BC) soil, a lot of engineers are worried about construction of durable as well as economical pavements laid on black cotton (BC) soil. Although BC soils are good for agricultural purpose yet these soils are not so perfect for building durable pavements. For any nation to be prosperous and developed, an efficient road network plays a vital role. For constructing a durable and efficient road network in BC soil region, the behavior of such soils should be thoroughly studied. These soils absorb water considerably and show heavy swelling due to presence of a clay mineral ‘montmorillonite’. This may lead to loss in shear strength and increase in compressibility of such soils, subsequently development to cracks in pavement. In the summer season, BC soils show significant shrinkage in its volume, leading to development of cracks. These soils depict extreme hardness and cracks when in dry state. The stability as well as performance of the pavements built on BC soils are highly influenced by the characteristics of sub grade and embankment because they serve as foundation part for the pavement. In this connection, use of a new material ‘RBI grade-81’ is frequently suggested to modify BC soil quality. RBI grade-81 may reduce the use of bitumen and aggregates and thus, it controls over emission of carbon. This may lead to eco-friendly construction practices of road. The use of ‘RBI grade-81’ may impart adequate strength in addition to durability to various layers of pavements. This literature deals with obtaining optimum quantity of the RBI grade-81 to be added with BC soil in order to alter its undesirable properties and providing it better strength. This paper also deals with some main reasons of poor condition of roads over BC soils and measures for improved construction practices with RBI grade-81.