A Novel Application of Red Mud in Improving Aging Resistance of Asphalt

Abstract Red mud, a kind of residue after extracting alumina from bauxite, can be a potential anti-aging agent because of its special structure for absorbing light components and retarding oxygen penetration of asphalt. Therefore, the study aims at investigating the feasibility of red mud as modifier of asphalt and most importantly, to improve aging resistance. Modified asphalt was prepared from different contents of red mud (0 %, 1 %, 3 %, and 5 % by weight of asphalt). Conventional asphalt tests and accelerated thermal and ultraviolet aging of asphalt were conducted. The aging of asphalt mixture preparation and asphalt pavement in service is analogous to oven aging and a self-designed ultraviolet aging in the laboratory. The change of chemical components of asphalt after aging was analyzed. The results show that the physical adsorption of red mud and asphalt affects the performance of asphalt. Compared with matrix asphalt, red mud-modified asphalt shows excellent high-temperature deformation resistance and elasticity properties. Moreover, the aging index of red mud-modified asphalts is smaller, and red mud inhibits the formation of carbonyl and sulfoxide during asphalt aging. The slight changes of asphalt performance after aging indicates that it has good aging resistance.