An experimental investigation on dense bituminous macadam (IRC- grading 2) mixes with coal ash

Abstract. India is a developing country, and the main source of power generation is coal based thermal power plants, contributing to more than 70% of the total electricity generated in the country [1]. The predominant byproduct of a coal-fired thermal power station consists of bottom ash and fly ash. Coal-burning in thermal power plants releases gaseous and particulate pollution into the environment affecting various aspects of the environment & human health, leading to premature deaths and illnesses [2, 3]. The present study investigates the impact of coal ash, more specifically fly ash & bottom ash on dense bituminous macadam mixtures of Indian Roads Congress (IRC) - Grading II when employed as a substitute for a portion of the fine aggregates & fillers. DBM specimens were made using four coal ash percentage of 0%, 9%, 18% and 27%, with the fly ash content keeping constant at 6% by weight in the mix as a filler. The optimal composition was chosen following an analysis of the outcomes of Marshall test. The findings demonstrated that the partial replacement of fine aggregates with coal ash in DBM mixes resulted in a moderately adverse impact on the Marshall tests parameters. By utilizing coal ash in DBM mixes, the present study partly solves the problem of heavy dumping & solid waste disposal problem of coal ash on land leads to sustainable road pavement construction.