Permeability Alteration of Low Plastic Clay and Poorly Graded Sand Using Lime and Fly Ash

Abstract

Work in this paper evaluates the effectiveness of soil treatment with lime and fly ash in terms of response with permeability and void ratio. The laboratory investigations were carried out on low plastic illite clay and poorly graded sand. Three different lime and fly ash contents (1%, 3%, and 5%) were considered for treatment purpose. After mixing soil with additives, a reaction period ranging from 3 to 14 days was allowed for the bond development between lime and fly ash with soil particles. From test results, it is found that plasticity indices decrease for clayey soil by adding both lime and fly ash. The reduction of the coefficient of permeability due to treatment with lime and fly ash is higher for clay than for sand. Permeability of the lime and fly ash treated clayey soil decreases subsequently up to 58–92% and 68–95% during a reaction period of 14 days. For sandy soil, under similar testing conditions, this reduction is 30–84% and 55–95% for lime and fly ash treated soil, respectively. The change in void ratio pattern with additives illustrates that sandy soil shows better formation with lime than fly ash, whereas clayey soil interacts better with fly ash than that of lime. Fly ash is found more effective than lime in decreasing the permeability of clayey and sandy soils (5–30%). The results indicate that the selected additives are effective for stabilizing both the low plastic clay and poorly graded sandy soil to utilize these soils as cladding materials for water bodies.