Experimental study on the mechanical evolution for waste tire rubber powder‐modified asphalt and its mixture considering the temperature characteristics in seasonal freezing regions

Abstract The study focused on preparing modified asphalt and its mixtures using waste tire rubber powder and polystyrene–butadiene–styrene (SBS). The modified asphalt was divided into two types: single‐doped waste tire rubber powder and SBS/waste tire rubber powder, and modified asphalt mixtures were prepared by dry or wet processes. Based on the temperature and freeze–thaw characteristics of seasonal freezing areas, the mechanical evolution for waste tire rubber powder‐modified asphalt and its mixture was analyzed. The results showed the following. (1) The waste tire rubber powder‐modified asphalt viscosity was closely related to the amount and particle size of rubber powder. A particle size of 60 mesh or 80 mesh and an amount between 18% and 25% were suitable. (2) Combined with dynamic mechanical analysis and needle penetration test, the single‐doped waste tire rubber powder‐modified asphalt with 80 mesh rubber powder particles and 18–25% rubber powder content was suitable. The SBS/waste tire rubber powder compound‐modified asphalt (SBS 3%; rubber powder 16%, particle size 80 mesh; aromatic oil 4%; stabilizer 3‰) had better high‐ and low‐temperature performance improvement. (3) The splitting tensile strength of modified asphalt mixture deteriorated rapidly during the first 10 freeze–thaw cycles, and then tended to stabilize. The SBS/waste tire rubber powder compound‐ or single‐doped waste tire rubber powder‐modified asphalt mixture had better frost resistance. (4) The unified calculation model for strength deterioration obtained by using a single logarithmic coordinate transformation could reflect the strength and deterioration rate through the material parameters. (5) At high or low temperatures, the modified asphalt mixture presented flexible or brittle failure, respectively, with a critical brittle failure temperature near −10 °C. While, the dry process modified asphalt mixture was not suitable for service in seasonal freezing regions. The study was used to further understand the mechanical characteristics of waste tire rubber powder‐modified asphalt and its mixture under environmental load in seasonal freezing regions. © 2024 Society of Chemical Industry.