Performance test of rubber asphalt based on domestic and abroad test methods

To unify the performance evaluation indicators of asphalt rubber, 70^# and 90^# base asphalts were modified with different rubber powder contents. The performance tests of rubber asphalts were conducted by Chinese specific tests such as penetration test, ductility test, softening point test and elastic recovery test, and Superpave methods such as dynamic shear rheology(DSR)test, Brookfield rotary viscosity test, and bending beam rheology(BBR)test. Analysis result shows that the addition of rubber powder can improve the high-temperature performance and reduce the temperature sensitivity of asphalt, but increase the viscosity of asphalt at high temperature and increase the difficulties in asphalt mixing and compaction. The swelling of rubber powder would lead big error in penetration test, so it is not recommended to apply penetration test in evaluation of rubber asphalt performance. Softening point can be regarded as one of evaluation indicators for high-temperature performance of rubber asphalt. For 90^# base asphalt, its softening point increases by 11.23, 11.97, 15.18 and 21.10 ℃ when the rubber powder content is 10%, 15%, 20% and 25% respectively. For 70^# base asphalt, its softening point increases by 4.02, 8.18, 12.83 and 14.45 ℃ when the rubber powder content is 10%, 15%, 20% and 25% respectively. It is also found the influence of softening point caused by rubber powder is larger on 70^# base asphalt than on 90^# base asphalt. The improvement of rubber powder on the low-temperature performance of asphalt would decease with the decrease of temperature. To test the improvement of rubber powder on the low-temperature performance of asphalt, BBR test is more significant than low-temperature ductility test. Besides, big error will produce in low-temperature ductility test process because of its small value. Therefore, it is recommended to apply BBR test for the low-temperature performance evaluation of rubber asphalt.