Requirement to Improve C.B.R value in Black Cotton Soil in Saline Condition: A case study of Bhavnagar-Dholera Highway in Gujarat, India

The Aim of this paper to define need to improve C.B.R value of subgrade in saline condition in black cotton soil. Expansive soil have tremendous strength but it become very soft when it getting wet, It expands/swell due to its mineralogical composition during its wet condition, It creates cracks or consolidated when it is dry. The stability and performance of the pavements are greatly influenced by the sub grade and embankment as they serve as foundations for pavements. Expansive soils can be found on almost all the continents on the Earth. Destructive results caused by this type of soils have been reported in many countries. The Saline soils have excessive concentration of natural soluble salts, mainly of chlorides, sulphates and carbonates of calcium, magnesium and sodium. The magnesium in magnesium chloride may react with the cement paste in concrete, weakening the pavement structure. Rutting or Pot holing in granular Pavement & Differential shape resulting in rough pavement. Both Expansion and Salinity influences pavement failure due to failure in sub grade so it is required to detail study on stabilization of black cotton soil. Flexible Pavement design is based on C.B.R value and m.s.a value. If value of C.B.R is low than thickness of material is going to increase hence for economical thickness need to improve C.B.R value where it is low.