Effect of fillers and their fractional voids on fundamental fracture properties of asphalt mixtures and mastics

A laboratory investigation was performed to evaluate the influence of filler type and Rigden fractional voids on fundamental fracture limits of asphalt mixtures and mastics. Fracture properties of 14 different asphalt mixtures and mastics composed by the combination of 7 different fillers and 2 asphalt binders were evaluated using: a visco-elastic fracture mechanics-based crack growth law for mixtures; the Bending Beam rheometer for mastics at low temperatures and a Modified Direct Tension Test for mastics at intermediate temperatures. A Digital Image Correlation System was employed to detect strain distribution and damage evolution in mastics. Experimental results indicate that the filler type and Rigden fractional voids affect the fracture limits and the definition of strain distribution and damage evolution of both mixtures and mastics, while other properties result more dependent on the physio-chemical interaction between filler and asphalt binder.