Stabilization of Black Cotton Soil Using Lime and Bamboo Fiber Mixture as a Subgrade Material

Abstract

Abstract: The design of pavements on black cotton soil has always been a difficult task for the engineers as the structure and pavement resting on black cotton soil cracks without any warning. Black cotton soil is most commonly found in Indian region. Soil proportion changes depending upon their constituents, i.e., water content, density, bulk density, compressive strength etc. The properties of black cotton soil can be modified by stabilizing the soil with the use of additives or by mechanical means. The aim of this project is to find the optimum percentage of lime separately and lime + bamboo fibre separately to be added in black cotton Soil and study the properties of soil. In this project an attempt has been made to stabilize the soil using lime and bamboo fibre. Initially lime is blended with black cotton soil in different proportions (2%, 4%, 6%, 8%). The experimental work included the tests carried out on virgin black cotton soil and lime added black cotton soil which are Liquid limit, Plastic limit, modified proctor, specific gravity, free swell index, C.B.R. test, unconfined compressive strength test. On the basis of the soaked CBR and Modified Proctor Values, it is determined that 6% of lime is an optimum percent which can be added to stabilize black cotton soil for road construction. So, 6% lime is added with black cotton soil and different percentages of bamboo fibres (2%, 4%, 6%, 8%). California Bearing Ration, modified proctor test, Unconfined Compressive strength test are performed on the soil mixture of 6% lime + Black Cotton Soil + different percent of Bamboo Fibre. On the basis of the soaked CBR, it is concluded that if 6% lime with 8% of bamboo fibre is blended in black cotton soil, engineering properties of BCS can be improved to such an extent that the pavements built on this soil can efficiently withstand the loads applied on it while vehicular movement. Hence, according to the results obtained from experimental study, pavement design is performed for CBR 5%, 6%, 8%. The evaluation of cost for each pavement design is carried out which shows the decrease in cost of construction of pavement as the CBR values increases.