Using bauxite as alternative for coarse aggregate in asphalt mixture: Improving skid resistance

Abstract

The depletion of natural resources promotes to search for alternative of virgin pavement materials with the aim of ensuring the performance of pavement especially skid resistance, which is often linked to financial and health services of the country. To solve the issues, the paper attempts to employ bauxite as alternative for coarse aggregate of surface layer to improve skid resistance. To this end, the performance of calcined bauxite aggregate was characterized on the basis of some laboratory tests. Thereafter, radar chart method was used to evaluate the comprehensive skid resistance of different aggregates, followed by preparing asphalt mixture based on optimization results. Currently, the skid resistance of asphalt mixture composed of different aggregate was examined by the three-wheel polishing device (TWPD) combined with dynamic friction tester (DFT). After the process, the multiple linear regression model was performed considering the morphological, mineral and chemical characteristics of aggregate with the aim of predicting the long-term skid resistance. As for physical and mechanical properties, the different grades of calcined bauxites show an increase about 20%∼200% compared with limestone. From the radar chart method, it was observed that calcined bauxite, especially 88# calcined bauxite, was found to exist highest comprehensive skid resistance. It is obvious that the model involving mineral and chemical properties is able to exist higher accuracy, adjusted R2 having values even exceed 0.9. In addition, it was found that the cost-benefit of 88# calcined bauxite and 75# calcined bauxite were 22.82 and 12.70 respectively. Herein, the study allows us a feasible approach to ensure the demand of pavement and mitigate the challenge for environment.