Stabilization Of Expansive Sub Grade Soil By Wheat Husk Ash And Lime

Abstract

Expansive soil is very sensitive to variation in moisture content and exhibit large volume change. This behavior is attributed to the presence of montmorillonite mineral. Extensive spread of the black cotton soil has posed challenges and causes more damage to light building and pavements than any natural hazard. To encounter with it, there are various methods to improve the strength of the soil, such as mechanical compaction, dewatering and earth reinforcement. And other methods like stabilization using admixtures are more advantageous. In addition to this, the innovative and nontraditional research on waste utilization is gaining importance now days before resting any structure on expansive soil. Some of soil improvements using admixtures are rice husk ash, wheat husk ash, lime, cement, blast furnace slag, fly ash etc. The main objective of this study is to introduce an alternative method of stabilization of expansive soil and to evaluate the effects or performance of soil using wheat husk ash and lime as soil stabilizing materials. The samples of lime taken from Zuway lime factory, the expansive soil collected from Welenchity and Wheat Husk Ash from Arsi region. A number of trial mix of laboratory test has been conducted on using soil mixed with lime as 0%, 2%, 4%, 6%, 8% and 10% blended with Wheat Husk Ash in 0%, 3%, 6% 9% and 12% by weight of dry soil. The laboratory test results show that a significant increase in CBR and UCS strength. The Soaked CBR values increases from 3.25% to 27.86% and UCS improved from 87kN/m2 to 802.94kN/m2.The free swell of the expansive soil is reduced by 29.8% with increase in Wheat Husk Ash content from 0% to 6%. From this investigation it can be concluded that the combination of lime and Wheat Husk Ash has a potential to improve the engineering performance of expansive sub grade soil.