STUDY OF SOIL STABILIZATION OF BLACK COTTON SOIL USING KOTA STONE DUST

Abstract

This project report shows the result of laboratory study to investigate Kota stone dust mixing with black cotton soil and its effect on index properties of black cotton soil. Black cotton soil is very weak soil to bear the load of the structure and contains swelling and shrinking and highly compressible properties whenever change in water content takes place. So it is required to make it suitable for construction activities. So that improvement of black cotton soil is required with the mixing of admixture like as Kota stone dust. The essence of this project is to check out the feasibility of Kota stone dust as soil stabilization material. Number of laboratory experiments is required to investigate the effect of Kota stone dust with black cotton soil with the different proportion of it with 0% to 30% in the interval of 5%. Test results represent a quite change in consistency limit or Atterberg’s limit. Liquid limit decreases from 53.26% to 37.8%. Plastic limit changes from 29.76% to 29.12% with a very slight change in mixed proportion of soil. Liquid limit and plastic limit of black cotton soil decreases with increase in proportion of Kota stone dust. A big change is found in liquid limit but slight change in plastic limit takes place so overall plasticity index which shows plasticity behavior of soil also decreases up to a great extent. Plasticity index decreased from 23.5% to 8.68% with the addition of Kota stone dust from 0% to 30%. The differential free swell index decreased from 64.24% to 39.82% which shows that a reduction in swelling property of soil due to increase in the proportion of Kota stone dust which is a pozzolanic material and exerts friction in it due to coarser size particle of pozzolanic Kota stone dust. The unconfined compressive strength of soil is found maximum when Kota stone dust is mixed 10-20% with black cotton soil. The unconfined compressive strength of soil increases up to a certain limit after that it decreases. We found maximum UCS strength at the mixing of 15% Kota stone dust. Black cotton soil showed good UCS strength in the range of 10- 20% Kota stone dust. When soaked CBR test was performed so that improvement in CBR value was found maximum within the range of 20-25% mixing of Kota stone dust, it gives maximum CBR value so it is desirable to mix Kota stone dust in black cotton soil with a proportion of 20- 25% of mixing. CBR value mainly shows the soil behavior according to highway projects so Kota stone dust is useful in highway pavement design because it shows pozzolanic behavior of soil and frictional properties that causes good binding found in soil. Kota stone dust mixing with black cotton soil increases its maximum dry density in the range of 15-25% mixing of Kota stone dust. We found that in the range of 15-25% Kota stone dust maximum compaction of soil occur So it is helpful to make the soil dense by providing proper compaction and maximum dry density of soil. Standard Procter test was performed with heavy compaction during experiments so that it was found that dry density of soil increases up to a particular proportion of Kota stone dust in the range of 15-25% but continuous increase in water content was found with increase in its proportion. So a range of 15-25% is batter to make a highly compacted and dense soil. So that lots of experiment has conducted during this project and results are positive to stabilize soil by mixing of Kota stone dust mainly in the range of 15-20%. This range shows best mixture of kota stone dust with black cotton soil because all the laboratory results are giving satisfactory improvement in the geotechnical.