Stabilization of Expansive Soil with Corex Slag and Lime for Road Subgrade

Abstract

Huge quantities of industrial waste are generated every year all over the world. An enormous amount of this industrial waste material is getting discarded at the landfilling site. If examined properly, an appropriate amount of this material can be employed in road construction sector. Even in developing countries, only a specific kind of waste materials is underused and that too on an experimental basis. Present investigation describes the behavioral aspect of expansive soils mixed with industrial waste Corex slag with lime to improve the load-bearing capacity of the soil. Corex slag was mixed with the expansive soil in the range of 10% to 30% with an increment of 5%. Lime was added by 2% and 4% in the mix by the dry weight of soil. The physical and chemical properties of soil + Corex slag + lime mixes were determined. Various parameters like specific gravity, Atterberg limits, pH, compaction, UCS, and CBR were determined to understand the effect of these blends. The microstructural investigation of Soil, Corex slag, and the lime mix was done by using SEM and XRD technique. The specific gravity of combination was increased with increased Corex slag percentage. The MDD of soil + Corex slag + lime also increased as the Corex slag have high specific gravity. Admixing of all these stabilizers improves soaked CBR and UCS values. The addition of 25% Corex slag with 4% lime in the soil gives an optimum mix. The UCS value of the soil increased from 0.24 MPa to 1.09 MPa with the optimum combination. The CBR value of samples increased from 1.86% to 53.52% at the optimum mix proportion. The strength of expansive soil with the addition of Corex slag and lime had improved significantly due to the formation of CSH, and CASH gel as confirmed by XRD analysis. The increment in the strength explained by the changes in microstructure, observed from SEM analysis. This experimental analysis supports the usage of Corex slag for stabilizing expansive soil with some percentage of lime for subgrade layer in Highway construction.