Experimental evaluation of industrial waste powders as fillers in hot mix asphalt by response surface method

Waste materials can be effectively utilised in road pavement and recycled to minimise environmental damage while saving costs associated with producing raw materials and utilising natural resources. This paper investigated the use of dried ceramic sludge (DCS) and press mud (PM) derived from the raw sugar beet syrup process, comparing their performance with that of conventional filler limestone powder in hot mix asphalt. For this purpose, samples were created based on varying percentages of filler and bitumen content, ranging from 4% to 8% in two steps and 5% to 6% in five steps. Subsequently, for each sample type, the filler and bitumen percentages were determined separately after conducting tests using the response surface method. Ultimately, for the optimal content of each filler, different samples were prepared again for the Marshall stability test, resilient modulus, indirect tensile strength, index residual strength, tensile strength ratio, long-term aging, and Cantabro loss. The results of the experiments indicated that both new fillers surpassed the limestone powder. DCS significantly enhanced the strength, resilient modulus, moisture sensitivity, and durability of asphalt mixes. These findings demonstrate that DCS and PM, as industrial waste, can be incorporated into asphalt mixes to reduce pollution and safeguard the environment.