Analysis of cracking resistance of bituminous mixtures under monotonic and cyclic loads

Although cracking resistance is one of the most important properties affecting the durability of asphalt mixtures, this property is often not considered as a requirement in the mixture design stage, and the bitumen content is determined from other properties (voids content, permanent deformation, or water sensitivity, etc...). The effect of bitumen content on the cracking resistance of an asphalt concrete mixture (type AC) was analyzed in this paper by means of different types of tests. Firstly, a cyclic strain sweep test (EBADE test) was used to obtain the evolution of the complex modulus and dissipated energy density with the number of cycles as well as the failure strain. Results from a previous research study helped approximate the fatigue laws of the mixtures studied, providing insight into the effect of binder content on the fatigue life of the mixtures manufactured with 3, 4, 5, and 6 % of binder by mixture mass. Secondly, a direct tensile monotonic test (Fenix test) was used to determine the strength and fracture energy of the mixture. The mixture with the 5 % binder content exhibited better results in all tests, indicating that this value would be the optimum binder content as it showed good consistency between the cyclic and monotonic tests employed.