PHYSICO-CHEMICAL CHANGES IN SOIL DUE TO SULPHURIC ACID CONTAMINATION

Acid contamination of soil can adversely affect the geotechnical properties of soil even at low concentrations. The effect of sulphuric acid contamination (0-15%) on the behavior of three types of soils viz., black cotton soil, a dispersive soil called Suddha soil and a red loamy soil with varied clay content has been studied. Specific surface of all the soils decrease due to acid contamination. The liquid limit decreased for all the three soils with increase in sulphuric acid concentration generally due to increase in electrolyte concentration of the pore fluid and consequent decrease in the thickness of double layer developed. This indicates the reduction in water holding capacity and increase in the frictional resistance and decrease in cohesion in soil. With increase in acid concentration the cation exchange capacity of soils decreases. There is a decrease in the optimum moisture content of soils. Unconfined compressive strength has significantly reduced due to loss of cohesion.