Effect of basalt powder and metakaolin fillers on asphalt mastic behavior

Abstract

Asphalt mastic is the mix between filler and the asphalt binder that can influence the mixture's compaction characteristics and the optimal asphalt content. Filler is defined as the mineral portion that passes through the sieve nº. 200 and it acts in the asphalt mixture by filling voids and modifying the viscosity, elasticity, and thermal susceptibility of asphalt binders. This study sought to determine the influence of different filler types and amounts on asphalt mastics' behavior. For this, physical tests, such as penetration, softening point, ductility, and elastic recovery were performed to evaluate the characteristics of binder and mastics with filler addition. The filler types used were basalt powder and metakaolin in the proportion of 0.6 and 1.2 filler/asphalt. The fillers' additions significantly influenced the mastic, and metakaolin had a more considerable effect on asphalt binder behavior than basalt powder. It made the mastic more rigid, more viscous, less elastic, and less susceptible to temperature. These changes are strong insights that the filler insertion improves the mixture performance regarding fatigue cracking and permanent deformation.