Mixed mode fracture behavior of concrete pavement containing RAP - 3D finite element analysis

Reclaimed asphalt pavement (RAP) is commonly used to improve the sustainability of asphalt concrete pavement. The main objective of the present work is to study the effect of RAP content on the mixed mode fracture behavior of concrete pavement numerically. An extended finite-element model was adopted to simulate crack growth under mixed mode loading. Semi-circular bending (SCB) specimen was used with three different crack geometries, namely inclined crack at the middle with different inclination angles (SCB-1) and vertical crack subjected to asymmetric three point bending. The effect of specimen geometry on the mode I fracture toughness (KIC) has been studied. The relationships between both RAP content and specimen geometry and mixed mode fracture toughness have been correlated. It is found that, the present 3D finite element model is a good candidate to predict the fracture behavior of concrete pavement containing RAP. To examine the reliability of each type of specimen geometry for predicting KIC, the maximum undamaged defect size (dmax) concept has been applied. It is found that, KIC predicted from the classical SCB (SCB-1) is reliable compared the values predicted from the other specimen geometries. Where the ratio of dmax to the maximum aggregate size (dmax/MAZ) ranged between unity and 2 in the case of SCB-1, it ranged between 5 and 14 in the other cases. Furthermore, the relationship between the present numerical values of KIC predicted from SCB-1 specimen and the flexural strength measured experimentally by Hossiney et al. (2010) is strongly correlated.