Research Article STABILIZATION OF SUBGRADE BY CEMENT WITH NATURAL ADDITIVES

Abstract

Stabilization of soil refers change or modifies the soil properties by adding suitable additives to it. Stabilization method depends upon number of factors like type of terrain, type of soil, nature of construction methods etc. The subgrade should have a strong nature so that it can carry enough loads. Effective use of additives in laterite soil will increase its strength characteristics. The usage of natural material provides environmental sustainability and they have less toxicity. Natural materials can be used as a cost effective and environmental friendly material for increasing the strength characteristics of the soil. In this study cement, plastic waste in the form of plastic strips (PS), rubber latex (RL), and coir fiber ash (CFA) were used as the stabilizing agents for laterite soil stabilization. Plastic waste in the form of plastic strips was used as the stabilizing agents. Addition of plastic strips causes an increase in strength of soil due to the ductile property of plastic. India is the second largest producer of cement. Cement act as a good binder to soil. When it comes in contact with water the soil-cement becomes harder. It provides brittleness to soil. The usage of CFA helps to reduce the environmental impact due to agricultural waste. Presence of lignin in coir fiber imparts good strength. Coir Fiber is one of the waste produced from agricultural industry. RL preserves the CFA mixed soil and thereby increase the durability of the soil mix. Series of compaction tests were conducted to get the best combination of the above mentioned additives. Apart from compaction test, unconfined compressive strength (UCS) test, California bearing ratio (CBR) test were also conducted. For the test, varying percentage of plastics and cement were added to the soil, varies from 0.4% to 1.2% and 0.5% to 3% respectively. Test results show that 0.8% plastic waste and 1% cement gives the best result. Similarly RL content varied from 5% to 30% and CFA varied from 0.5% to 4%. A combination of 25% RL and 1% CFA showed satisfactory increase in the strength of the soil.