Effect Of Mineral Filler Type And Content On Rheological Properties Of Asphalt Mastic

Asphalt mastic is composed of mineral filler and asphalt binder,which is an important part of asphalt mixture.In practical engineering,it's offen happened that the change of mineral filler types leads to great changes in the road performance of asphalt mixture.But the reachers only focus on the performance of asphalt binder,attempts to correlate the performance of asohalt binder directly with the performance of asphalt mixture,regard the mineral filler as inert filler,and lack a unified and effective evaluation system for asphalt mastic.The asphalt mastic was successfully prepared basing on penetration 70 asphalt with limestone filler,cement and hydrated lime.The F/A(filler to asphalt ratio)ranged from 0 up to 1.5 in ratio increaments of 0.3.the paper studed the effect of type and content of mineral fillers on rheological properties of asphalt mastic by using Superpave system.The PG grading method of asphalt mastic was put forward,and the correlation between the conventional test index and the Superpave index was analyzed.The technical indexes,such as rut parameter,creep stiffness,stiffness change rate and average non-recoverable creep compliance,of asphalt mastic were analyzed based on Superpave tests.The Superpave tests results and analyses indicate that the three mineral fillers can effectively improve asphalt mastic's high temperature rutting resistance and temperature sensitivity.And the effect of limestone and cement on improving the high temperature rutting resistance is more abvious.Mineral fillers have negative effects on the low temperature performance of asphalt mastic.Based on Superpave asphalt binder PG grading system,proposed to use the critical value of rutting parameter,fatigue cracking parameter,creep stiffness and stiffness change rate as the grading index to asphalt mastic PG grading.The results show that the mineral fillers can improve the grading high temperature,and the cement and hydrated lime have a greater improvement.The mineral fillers have negative effects on grading low temperature.The mineral can improve the middle temperature of asphalt mastic,but it can still meet the requirement of the specification.In addition,mineral fillers can also expand the applicable temperature range.The penetration test of asphalt mastic was carried out,and the correlation between the penetration index and Superpave index was analyzed.The test results and analysis show that the mineral fillers can effectively improve the high temperature performance,temperature sensitivity and aging resisitance of asphalt mastic.In addition,there is a good correlation between the penetration index and Superpave index,and two evaluation methods are consistent to evaluate the asphalt mastic.