EVALUATING COMBINE EFFECTS OF BASALT-HYDRATED LIME FILLER ON LOW-TEMPERATURE PERFORMANCE OF VIRGIN AND POLYMER MODIFIED ASPHALT MASTICS

摘要

The present study evaluates effect of Hydrated Lime (HL) on low temperature performance of asphalt mastic prepared with unmodified and modified asphalt binders. The asphalt mastics were produced in the laboratory using VG-30 and Polymer Modified (PMB) binders with different combinations of basalt (B)-HL fillers. The dosages of HL were selected as 0%, 5%, 10%, 15% and 20% by weight of asphalt binder, and percentage of B filler was adjusted accordingly to meet a constant filler to binder (F/B) ratio of 0.8 (by mass ratio). The thermal cracking behavior of asphalt mastics was evaluated using bending beam Rheometer (BBR) test at different low temperatures. Further, the low temperature .thermal cracking behavior of VG-30 and PMB mastics were evaluated based on creep stiffness, rate of relaxation properties and master curves over loading time domain. Overall test results indicate that elemental properties of binder and mineral filler and weight concentration of HL filler have a significant effect on thermal cracking resistance of VG-30 and PMB mastic. The results from BBR test showed that the combination of HL filler with B filler enhanced the thermal cracking resistance (decrease in creep stiffness with increase in rate of relaxation) of VG-30 mastic, especially with a low concentration of HL (5%). However, the combination of B with high dosages of HL filler may not beneficial to enhance the thermal cracking resistance of PMB mastic.