Sustainable pavement solutions using coal reject waste and plastic waste as aggregate replacements

The growing demand of natural aggregates and the environmental degradation brought about by the industrial and plastic wastes mandate the need to seek sustainable solutions in pavement engineering. This study explores the utilization of coal reject waste and plastic waste as partial aggregates in place of bituminous concrete. Coal reject replacement levels were selected in the range of 20%–60%, plastic contents were selected in the range of 5%–20%, and mixes were tested through standard IS ASTM and MoRTH tests. Findings reveal that the integration of these wastes in combined form has a significant effect on improving the performance of pavements. The optimum mixture (C40P10) had a bulk density of 2.36 g/cm3, Marshall stability of 13.2 kN, tensile strength ratio of 86%, rutting depth of 5.1 mm, and fatigue life of 21 000 cycles. Besides enhanced mechanical strength, durability performance, and economic benefits, there is a significant reduction in CO2 emissions. The results verify that coal reject-plastic modified bituminous concrete provides a sustainable, cost effective, and high performance substitute in building flexible pavements.