Experimental evaluation of the effects of crack relief interlayer on the fracture properties of asphalt mixtures

Recently, reusing recycled asphalt pavement (RAP) has played an important role as a eco-friendly interlayer for enhancing the fracture properties of asphalt mixtures due to the lack of energy resources and the significat role of economic and environmental aspects. Thus, the aim of this study is to investigate the effects of different interlayer types on reflective cracks propagation. In this study, the fracture properties of asphalt slabs with 4 different interlayers (sand asphalt, cement-stabilized base, reclaimed asphalt pavement (RAP) and bitumen-stabilized RAP) and three modes of cracks in the specimen (middle cracks, lateral cracks and double cracks) using three-point bending test have been evaluated. Finally, the results of this study indicated that bitumen-stabilized RAP interlayer had a better performance in comparison with the other interlayers. In addition, the fracture force in the samples with bitumen-stabilized RAP interlaxyer is higher than other samples; however, its fracture energy is lower due to less deformation than sand asphalt interlaxyer, which can increase the bitumen required for stabilization of reclaimed asphalt pavement (RAP) or use bitumen rejuvenating materials.