Analyses of tensile failure properties of asphalt-mineral filler mastics

This paper is intended to verify the concern expressed by researchers that stiff asphalt-mineral filler mastics may lead to the cracking of flexible pavements in the brittle-ductile region. Test results obtained from the direct tensile test show that both tensile stress and tensile strain increase with increasing mineral fillers. The failure energy of asphalt-mineral filler mastics also increases with filler concentration because of increases in strength and strain. With increasing tensile strength, it is implied that there is a good adhesion between asphalt binders and mineral fillers. The tensile strength of asphalt-mineral filler mastics decreases as the size of filler particles increases. However, at very low temperatures plain asphalts and mastics exhibit low strains, indicating that mineral fillers may not be the cause of cracking. Interaction mechanisms between mineral fillers and asphalt binders are proposed to explain the increase of stress and strain. After reviewing various composite models, a particulate-filled composite model is selected to accurately predict the tensile strength of asphalt-mineral filler mastics.