Engineering and Resilient Properties of Local Clayey Soil Improved by Fly Ash and Cement for Pavement Subgrade

Abstract

Soil for the subgrade of a pavement as represented by satisfactory engineering and strength properties, is usually preferred. Generally, poor soil for subgrade is improved by use of additives like lime, cement, etc. However, cost being a concern, locally available or waste materials like fly ash are chosen for soil improvement in the subgrade layer. This also helps in minimizing the concerns of pollution, besides reducing the cost. This motivates the authors to use fly ash with clayey soil, each locally available to reduce the plasticity and make it suitable for subgrade. This paper encompasses a systematic laboratory study of use of fly ash and ordinary Portland cement (OPC), from improvement of consistency properties to strength characteristics including resilient modulus. The present study concluded that the clayey soil modified with 30% fly ash and 2% cement (each material available locally) results in a considerably improved soil for use in the subgrade of a pavement subjected to high volume traffic.