Design and Cost Analysis of Flexible Pavement Constructed Using Rice Husk Ash and Brick Kiln Dust.

The escalating challenges of waste management and the increasing demand for sustainable construction practices have spurred growing attention to the innovative use of waste materials in various construction applications. Past studies reveal that the incorporation of waste materials into construction processes has contributed to environmental sustainability by reducing the burden on landfills and conserving natural resources. This paper explores the diverse range of waste materials being re-purposed in construction, including, agricultural residues of rice husk called rice husk ash and industrial by-products from brick kilns called brick kiln dust (BKD). Various laboratory tests including differential free swell, Atterberg's limits, modified Proctor, unconfined compressive strength, and California bearing ratio, were performed on black cotton soil (BCS) alone and in combination with varying percentages of rice husk ash and brick kiln dust. Additionally, the thickness of the flexible pavement was evaluated for various optimum combinations based on California bearing ratio values and finally, economic feasibility associated with the use of waste materials was addressed, providing insights into the overall sustainability of such practices. Also, the laboratory test indicates an improvement in the geotechnical characteristics of black cotton soil by adding an optimum amount of RHA (20%) and BKD (15%) alone and in combination with each other. Moreover, the required thickness for the flexible pavement was found to be reduced corresponding to each million standard axels loading conditions. Furthermore, it is evident from the results that the cost of the flexible pavement was substantially reduced for all the optimum mixes and the highest economy of 65% has been achieved corresponding to BCS:RHA:BKD::65:20:15. [ABSTRACT FROM AUTHOR]