STABILIZATION OF BLACK COTTON SOIL BY LIME AND POLYPROPYLENE FIBRES

Abstract

A large part of Central India and a portion of South India are covered with black cotton soils. These soils
have high swelling and shrinkage characteristics and extremely low CBR value. Hence, there is need for improvement of
these properties. The practice of using reinforced earth has been well established in soil engineering profession. The
concept of reinforcing soil masses with artificial fibers is a relatively new development to improve the properties of soil.
The present study is aimed at determining the behavior of black cotton soil reinforced with polypropylene fiber in a
random manner.
This project describes the compaction and strength behavior of black cotton soil (BC soil) reinforced with
polypropylene fibers. In order to increase the strength of the soil-polypropylene fiber combination, optimum percentage
of 2% of lime is added. The soil used is a type of black cotton soil collected from collected at a depth of 2m below the
ground level from Tikota which is 25 kms away from the Bijapur city. The fibers are available in different lengths (6mm,
12mm) and mixed randomly with soil in varying percentages (0.50%, 1.0%, 1.5%, 2.0%, 2.5%, and 3%) by dry weight of
soil and compacted to maximum dry density at optimum moisture content. The test results indicate a reduction in the
maximum dry density and increase in the optimum moisture content of soil due to the addition of polypropylene fiber. It
also indicates an improvement in the CBR value of soil due to the addition of polypropylene fibers. BC soil treated with
2% lime and reinforced with polypropylene fiber shows ductility behavior before and after failure.