Mode I fracture resistance of hot mix asphalt and warm mix asphalt

Abstract

Pavement cracking is a major pavement distress and its rehabilitation cost is astronomical. Low temperature cracking and bending cracking due to cold climate and traffic loading are two major pavement distresses in asphalt concrete pavements. In this paper, the fracture resistance of cracked asphalt concretes made from two different types of asphalt mixtures i.e. hot mix asphalt (HMA) and warm mix asphalt (WMA) are compared. Three-point bending tests were performed using semi-circular bend (SCB) specimens at -10°C and the critical mode I stress intensity factor KI was then calculated using the peak load obtained from the load-displacement curve. The SCB samples were prepared from gyratory compacted cylinders. Crack within the sample was generated utilizing a water-cooled sawing machine with a thin blade. The results showed that the critical stress intensity factor of HMA is higher than that of WMA. The indirect tensile strength (ITS) tests were also applied to asphalt mixtures and it was found that WMA has greater strength compared with HMA. Also the results from static creep test showed that the WMA behavior is much more elastic than HMA mixture. Therefore, asphalt mixture type has an important role in fracture behavior of asphalts concretes.