EVALUATION STUDIES OF FLEXIBLE PAVEMENT SYSTEM LAID ON EXPANSIVE CLAYS TREATED WITH DIFFERENT CHEMICAL ADDITIVES

Expansive soils undergo alternate shrinkage and swelling due to moisture fluctuations and posses low strength in rainy season due to poor drainage conditions. As a result, flexible pavements constructed over such soils are not only expensive but also result in poor performance and premature failures. Flexible pavement construction in expansive soils is expensive due to large pavement section resulting from low CBR values in wet condition. The volume instability of soil affects constructed pavements and demands frequent maintenance. Hence efforts are to be made for reducing large pavement section and also to suppress swelling of sub grade. Hence efforts are to be made for reducing large pavement section and also to suppress swelling of sub grade. Though the use of granular and CNS cushions in pavement construction helps in reducing volume changes affecting pavement layers it cannot reduce required large pavement sections. Hence, this paper reviews some of the key advances developed over the past 60 years in improving our understanding of the nature and methods of modifying and stabilizing expansive clay soils. The main objective of this work is to study the swelling properties of the expansive sub grade soil treated with chemicals like lime, cacl2 and also by adding Fly ash based Geopolymer in varying percentages. The swelling properties of the collected expansive soil samples were determined based on the parameters like Free Swell Index, Swell Potential and Swell Pressure.