Effect of bitumen type and content on the cracking resistance of asphalt mixtures at different temperatures

Abstract

Bitumen type and content are two of the variables that most influence on the cracking resistance of an asphalt mixture, since both determine a more or less ductile fracture. Furthermore, this cracking resistance will be different depending on the temperature at which the mixture is exposed and is especially critical at low temperatures. The effect of bitumen type and content on the cracking resistance and fracture energy of an asphalt concrete mixture is analysed in this paper, by means of a new direct tensile test, Fénix test. With the aim of covering a wide range of performances, three different bitumens were used: a conventional 50/70 penetration bitumen, considered as the reference binder; a crumb rubber modified bitumen, which gives flexibility of the mixture; and a low penetration bitumen, which provides more stiffness to the mixture. The test was carried out at different temperatures to evaluate the effect of low temperatures at which the mixture may be critical against cracking phenomenon.