Rheological characterization of high-content rubber modified asphalt considering particle size distribution

The use of ground tire rubber (GTR) in asphalt is a promising methodology to consume the waste tires as well as achieve high pavement quality. The pre-treatment technology will increase the GTR consumption in asphalt but varies the rubber particle size distribution and hence the asphalt rheological properties. This study aimed to investigate the impact of crumb rubber particle size distribution on the rheological properties of rubber-modified asphalt. To achieve this, the thermal filtration method was employed to separate and measure the different particle sizes for rubberized asphalt with different content and pre-treatment technology. Rheological tests were adopted to characterize the rutting, fatigue, and low-temperature performance of different rubber modified asphalt. Results showed that the increase in rubber content will cause a decrease in large particles (>300 μm ) and an increase in small particles (75 μm –0.22 μm ) and micro-particles (<0.22 μm ). A higher proportion of large particles enhanced high-temperature deformation resistance while compromising low-temperature cracking resistance. A large proportion of medium (300 μm –75 μm ) and small particles (75 μm –0.22 μm ) improved the high-temperature and fatigue resistance, indicated by reduction of non-recoverable creep compliance ( Jnr ) and a larger value of Nf. Additionally, a higher proportion of micro-particles (<0.22 μm ) significantly improved low-temperature cracking resistance. The aforementioned findings are expected to emphasize the rubber particle size distribution effect in asphalt and optimize the performance of high-content rubber modified asphalt in various temperature and loading conditions.