Performance properties of rubberized stone matrix asphalt mixtures produced through different processes

The study investigated the dynamic modulus, rutting resistance, moisture susceptibility and fatigue resistance
of rubberized Stone Matrix Asphalt (SMA) through laboratory performance tests. Rubberized SMA
mixes were produced by three processes: the dry process, the wet process and the terminal in the laboratory.
For comparison purposes, SMA mixtures containing styrene–butadiene–styrene (SBS) modified
binder and virgin asphalt of PG 67-22 were also evaluated and compared to rubberized SMA. Dynamic
modulus and direct tension fatigue tests were performed using the Asphalt Mixture Performance
Tester (AMPT) system. Rutting resistance and moisture susceptibility were analyzed by Hamburg wheel
tracking test using asphalt pavement analyzer (APA). The results showed that: (1) the incorporation of
CRM improved the high temperature dynamic modulus, the resistance to rutting and fatigue life of
SMA mixes. (2) The introduction processes of CRM (dry process and wet process) may have effect on
the high temperature dynamic modulus and rutting resistance, while no significant influence on the
moisture susceptibility and fatigue life. (3) The use of combination of SBS and CRM in the terminal
SMA significantly improved the resistance to rutting and fatigue cracking. (4) The rubberized SMA with
10% CRM had the lower performance properties than SBS SMA, regardless of the dry process or the wet
process.