Mechanical feasibility of using red mud as filler in asphalt mixtures to improve permanent deformation

• Main Authors: Mayara Sarisariyama Siverio Lima, Liseane Padilha Thives
• Format: Article
• Language: English
• Published: Associação Nacional de Pesquisa e Ensino em Transportes (ANPET) 2020-05-01
• Series: Transportes
• Subjects: Red mud; Permanent deformation; Filler.
• Online Access: https://www.revistatransportes.org.br/anpet/article/view/1847

Red mud is a solid residue that results when bauxite ore is processed to obtain alumina (aluminum oxide –Al2O3), the main chemical compound to produce aluminum. Brazil has a wide reserve of bauxite in Pará State and the ore is processed in large scale. However, in the country red mud is stored inadequately in the environment. Pará is situated in northern region of Brazil and presents high temperature throughout the year. The elevated traffic volume and the high temperatures contributed to the early appearing of defects in the flexible asphalt pavement surfaces. This laboratory study aims the introduction of the red mud as filler in dense asphalt mixtures to improve the permanent deformation resistance. Asphalt mixtures with 3%, 5% and 7% of red mud (range between 0.02 to 2,800 micrometers) were produced. A conventional mixture with 7% stone powder filler (maximum diameter of 0.075 mm) was used as reference. Permanent deformation resistance of the mixtures was evaluated through French Rutting Tester. As a result, the mixture with 5% red mud presented better resistance that obtained at 30,000 cycles, 3.5% of rutting percentage depth. The asphalt mixtures with red mud presented good performance, with reduction of the permanent deformation of 12.63 to 42.62% in relation to reference mixture. Red mud as filler in asphalt mixtures is a viable option to reuse this waste, as well as being an environmentally friendly alternative.