Study of Black Cotton Soil Characteristics with Cement Waste Dust and Lime

Abstract

Stabilization of soils is an effective method for improvement of soil properties and the pavement system performance. Plasticity Index is one of the important properties of soil to determine the behavior of soil in presence of water. The poorest soil among all is Black Cotton Soil (BC Soil). In Rajkot area this BC Soil is spread over southern part of District. Rich proportion of montmorillonite is found in BC Soil from mineralogical analysis. High percentage of montomorillonite renders high degree of expansiveness. These property results cracks in soil without any warning. These cracks have sometimes extent severe limit like 1/2 “to 12” deep. Use of this type of land may suffer severe damage to the construction with the change in atmospheric conditions. In this paper, BC Soil was tested using three different stabilizing agents - 1.Cement waste dust collected from the cement plant 2. Cement Dust + Lime Powder 3. Lime Powder. The cement waste dust was found best agent as a stabilizer to improve the Atterbergs’ Limit and hence Plasticity Index of BC Soil as well as the compressive strength of the same. Laboratory tests were performed with different percentages of three stages, each of them ranging from 1% to 9%. The behavior of BC Soil of Rajkot region was improved with stage no. 1, the percentage of Cement dust 7% of Cement dust in BC Soil is looking to be the appropriate mixing. Also in second stage, improvement is shown at 8% of combination of cement dust and Lime powder. Third stage was observed a best suited result at 9% of Lime powder in BC Soil. The results, thus obtained in laboratory under standard conditions provide satisfactory reason to use the Cement dust as a stabilizing agent for the purpose to improve Plasticity Index of BC Soil compare to other two combinations. After satisfying result of Plasticity Index, Cylindrical Samples of BC Soil with all three combinations were prepared to check the compressive strength of stabilized soil. Moisture content taken was the optimum percentage of plastic limit in each combination. The cylinders of size 50 mm in diameter and 60 mm height were tested after 3, 5, 7, 14, 21, 28 days. The relations for these periods were established among the use of all three different agents. Compressive strength of Cement dust stabilized BC Soil found more reliable.