Assessing High-Temperature Performance of Asphalt-Filler Mastic System Treated with Micro-Nano Filler Combinations

This work evaluates the performance of asphalt-filler mastic treated with a combination of inert-active fillers at high temperature. Inert filler does not react with asphalt, whereas active filler actively participates in a chemical reaction with asphalt. This study utilized a viscosity grade (VG)-30 asphalt, basalt stone dust (B), hydrated lime (HL), and nano hydrated lime (NHL) as fillers for asphalt-filler mastic preparation. The dosages of HL and NHL fillers were varied as 0%, 5%, 10%, 15%, and 20% by weight of VG-30. Filler/binder ratios of 0.6 to 1.2 were considered with different filler combinations (B, B-HL, B-NHL) for the production of 36 mastic types. The high-temperature performance of the asphalt-filler mastic was investigated using shear creep and multiple creep-recovery tests. Further, this study evaluated the properties of the fillers which were most influential on the permanent deformation behavior of mastic using grey relational analysis. The findings signify the beneficial effects of NHL over HL in improving the ability of mastic to withstand permanent deformation. Also, mastic treated with NHL was found to be less susceptible to high stress levels than mastic treated with HL. It was also found that the amount of active filler can be reduced by 5% (by weight of asphalt) by using NHL instead of HL to achieve the equivalent high-temperature performance of mastic. Specific surface area and average particle size were found to be the most two influential properties of filler that significantly influenced the high-temperature performance of the asphalt-filler mastic.