International Conference on Advances in Civil, Structural, Environmental and Bio-Technology - CSEB 2014
Author(s) : AYDIN KAVAK
Clayey and high plasticity fine grained soils usually create too much problems for earth fill works. In general, if the geotechnical properties of the existing soil are inappropriate, it is either replaced with a suitable fill material or improved on-site via various methods. This study investigated the use of lime to stabilize high-water-content high-plasticity clay for use in fill layers of an industrial region roads. Usually, drying of high-water-content clays is almost impossible at construction sites. At the beginning, MH high plasticity silt type of soil was dried first and then stabilized with hydrated lime and hydraulic lime at optimum water content and results of both lime are compared. The hydraulic lime was chosen for the real application and then, the research investigates the possibility of stabilizing high-water-content claywith a special lime called hydraulic quicklime without drying the soil. High plasticity soil was obtained from the Hadımköy district of Istanbul city in Turkey. Initially, Atterberg limit tests, sieve analysis and Proctor tests were performed on soil samples. The pH method indicted that appropriate lime content for stabilization was 3% by weight, and Atterberg limit tests were conducted at various lime contents. The original water content was 30-32%, which is very high compared to the 17% optimum water content of natural soil. The optimum water content increased to 18-21% with hydraulic lime. Hydraulic lime decreases the existing water in the natural clay soil during hydration and the water content of the mixture approaches the optimum water content of the clay soil with lime, resulting in large increases in strength of up to 14 times that of the natural clay soil. California bearing ratio (CBR) for soaked samples also increased from 4-6% initially to 40-75% with hydraulic lime, due to reduced swelling of the clay. The test results show that the soil becomes suitable as earth fill for road construction at the subgrade level and beneath. Quicklime additive improved the stabilization of high-water-content silty soil. Improvements to existing soils reduce the need for “cut and fill” during construction works, thereby reducing environmental impacts. This method is being applied in the field for the improvement of 550 000 m3 of clay and the work is going on.