UTILIZATION OFCONSTRUCTION WASTE –A USEFUL MATERIAL

Abstract

ABSTRACT Any structure has two fundamental parts - the sub-structure and the super-structure. Sub structure must be firm enough to withhold the super-structure placed over it. The properties of the soil get adversely affected due to swelling (due to wetting) and shrinking (due to drying). These lead to decrease in the bearing capacity of the soil and create problems during construction. To increase the capacity of soil to withstand different types of loadings, certain amounts of admixtures are added to it. These processes aimed at enhancing various soil properties are known as soil stabilization. Construction wastes resulting from infrastructure development are often a source of pollution and are hazardous. There is a need for effective disposal and preferably alternative utilization of these constructions wastes. The primary objective of this study is to explore the possibility of gainful utilization of these construction wastes for the purpose of soil stabilization. It is appreciated that if successful, this will lead to significant reduction in pollution and hazardous wastes. Besides, the easy availability of construction wastes will result in easy/improved soil stabilization/increased soil capacity. For this study on soil stabilization using construction wastes, the soil available in DTU campus and construction wastes available from different sources have been used. For soil stabilization several mixes of admixtures have been attempted. Most of these use lime as one of the admixtures. Different proportions of lime and construction waste by mixing it with expansion soil in using different methods have been studied. These mixtures are generally compacted to maximum dry density at optimum moisture content to find out the index properties, direct shear, permeability and California bearing ratio and compare the result are compare with virgin soil. These studies show that the soil properties improved because of soil stabilization using construction wastes. Various studies reported have however not indicated the optimum percentages of admixtures to achieve the maximum improvement in soil capacities. In this study, therefore, different proportions of lime and construction waste have been mixed with silty soil available within DTU Campus to recommend optimum percentages of these two admixtures. In order to conclude the same maximum dry density, consistency index, California bearing ratio etc have been at different proportions. Lime and construction waste mix in the range 5% to 15% to get optimum gain in strength (at OMC) has been studied. The experiments conducted in the laboratory indicate that the recommended optimum percentage of 5% lime and 10-15% construction waste mixed with silty soil is likely to give the for best. Key words: Lime, Construction waste, Permeability, OMC, Sub-grade, Direct shear test, CBR test.