Comparison of Industrial Waste Mixtures for Use in Subbase Course of Flexible Pavements

Abstract

The generation of huge quantities of waste materials from industries like iron, steel, thermal power plants, etc., is resulting in shortage of disposal areas and causing serious environmental pollution. In this paper, a comparative study of important engineering properties, namely unconfined compressive strength, triaxial shear strength, elastic modulus, resilient modulus, and permanent strain characteristics, of some industrial waste mixtures has been carried out for their use in the subbase layer of flexible road pavements. These materials, namely a Black Cotton soil–dolime (BCD) mixture, fly ash–dolime (FD) mixture, copper slag–fly ash (CF) mixture, and granulated blast-furnace slag–fly ash (GBF) mixture, were chosen based on the proximity of various industries that generate these materials as waste products. The behavior of these materials is also compared with that of conventional granular subbase (GSB) material. The values of deviator stress at failure of these mixtures were found to be greater than that of the granular subbase. Although BCD and FD mixtures exhibited higher elastic modulus and resilient modulus compared with GSB, the corresponding values were lower for CF and GBF mixtures. The prediction of resilient modulus was compared for different stress-dependent models, and the model constants of these mixtures for the best-fit three-parameter model are presented.