Numerical and experimental investigation of mode I cracking of asphalt concrete using semi-circular bending test

Mode I fracture toughness (K-IC) assessment procedure is presented in this study for semi-circular bend configuration. The geometrical factor f(a/w) is determined through 2D and 3D FEM simulations assuming linear elastic behavior. Parametric analyses have been done to evaluate the sensitivity of f(a/w) to the Poisson's ratio (v), specimen thickness (t) and position of the Gauss points where the vertical displacements are computed. The FEM analysis shows that f(a/w) is more sensitive to v in plane strain condition (thick specimens) than plane stress condition (thin specimen). Moreover, f(a/w) decreases slightly when "t" increases from 15 to 75 mm. In addition, f(a/w) evaluated from 3D FEM is slightly higher than that obtained in 2D configuration. The results also show that f(a/w) decreases when the position of the Gauss point is chosen far from the crack tip. Full factorial experimental program has been designed to evaluate the potential influence of: reclaimed asphalt (RA) content, loading rate and temperature on the fracture toughness (K-IC) and the total fracture energy (W-f). The results show that the influent parameters on the Kip can be ranked from the most important to the least one as follows: loading rate, temperature and RA content. They also show that temperature is the most influent parameter on W-f, while the loading rate is the least influent one. K-IC and W-f results have been modeled by polynomial functions. (C) 2018 Elsevier Ltd. All rights reserved.