Evaluation on performances of cold asphalt mixture containing recycled waste glass and red mud

The current study aims to assess the performance of cold asphalt mixture by incorporating recycled waste glass (e.g., 20% and 30% by weight of total mixture), and red mud, as substitutes for conventional aggregates. Laboratory tests were conducted to analyze the influence of waste glass on the workability energy index and compactability energy index. The resistance to cracking of asphalt mixture was evaluated using the indirect tensile asphalt cracking test, while assessments of rutting and moisture vulnerability were performed via the Hamburg wheel tracking test. Dynamic modulus test was also conducted to examine the response of the waste glass-modified asphalt mixture under dynamic loading and different temperatures. In addition, a 400-meter pedestrian road was constructed to evaluate the practical utilization of waste glass in real-world conditions. Results indicated that the addition of higher waste glass content reduced the theoretical maximum specific gravity due to density differences between waste glass and recycled asphalt. Increase in waste glass content led to a higher demand for compaction energy. The mixture containing 30% waste glass required over 22% more compaction energy compared to control mixture. While the 20% waste glass mix showed similar characteristics to conventional asphalt in terms of indirect tensile strength and rutting resistance. In contrast, the 30% mix exhibited notably weaker properties, which were 12% lower in CTindex and three times lower in stripping resistance. Dynamic modulus results showed that with 30% waste glass, the elastic behavior of asphalt mixture was strongly reduced. In general, the study recommended that the optimal utilization of waste glass in cold asphalt mixtures containing recycled asphalt and red mud appears to be at the 20% level, based on comprehensive laboratory and testbed results.