Performances of rubber asphalt with middle/high content of waste tire crumb rubber

Abstract

In order to study the performances of rubber asphalt (RA) with different middle/high waste tire crumb rubber content and preparation conditions, RA samples with 15–35% of rubber content, 170–230 °C of reaction temperature, 8–225 min of reaction time and 0–10% of aromatic oil (AO) content were prepared. The reaction mechanism between crumb rubber and asphalt was studied by micro and macro tests, and the fundamental properties, construction workability, storage stability, high and low temperature performances of RA were explored. The results showed that the crumb rubber in 15–35% RA only swells at 170 °C, while the crumb rubber swells first and then degrades at 190–230 °C. The swelling and degradation rates of crumb rubber increase with the increase of reaction temperature, the decrease of rubber content and the increase of AO content. The higher rubber content means higher softening point, ductility, elastic recovery and lower penetration of RA. Higher reaction temperature means higher penetration, ductility and lower softening point of RA. With the increase of AO content of RA, the penetration and ductility increase while the softening point and the elastic recovery decrease. The construction workability of RA promotes with higher rubber content and lower AO content. The storage stability of RA decreases with the increase of rubber content and the decrease of reaction time as well as the AO content. The complex modulus increases while the phase angle decreases when swelling is dominant, and the complex modulus decreases while the phase angle increases when degradation is dominant. The high temperature rutting resistance of RA increases with the increase of rubber content and the decrease of AO content. The low temperature crack resistance of RA increases with the increase of rubber content and AO content. The results could provide reference for the preparation of RA with middle/high content of waste tire crumb rubber.