Effect of differential thermal contraction on fracture toughness of asphalt materials at low temperatures

This study investigates the influence of differential thermal contraction on known fracture properties of asphalt concrete. The study hypothesis is that hairline cracks will develop in a mixture subjected to a sufficiently low temperature and that fracture toughness of the mixture will be substantially lowered. The objective of this study was to evaluate fracture toughness of asphalt concrete as affected by exposure to low temperatures. Fracture behavior of asphalt cement and asphalt-filler mixture were evaluated and compared with that of asphalt concrete. This paper presents the laboratory test procedures developed for fracture toughness applied to asphalt materials using the quasi-static three-point bending test setup and conducted at various low temperatures using materials common to Ontario, Canada.