Abstarct: Asphalt overlay is one of the most common methods for pavement maintenance. But the most important defect of this method is the diffusion and reflection of the failures and cracks in the underlying pavement into the overlay, which are referred to as reflection cracking. There are several factors that influence the occurrence of reflection cracking, so it cannot be completely prevented from its diffusion, it can only be postponed using a variety of solutions and slow down their growth and diffusion. Various studies have been conducted to delay the growth of these cracks and extend the service life of asphalt overlays. One of the most commonly used methods that the researchers have considered and has shown acceptable performance is the use of a crack relief interlaxyer between the existing cracked pavement laxyer and the overlay. For this purpose, geosynthetic products or a laxyer of sand asphalt are used. Today, due to the scarcity of energy resources, the economic and environmental role of reusing renewable materials is more and more important. These materials can also be used as interlaxyer in asphalt pavements. In this thesis, three-point bending test is used to investigate the effect of using these interlaxyers. The performance of four different interlaxyer types in asphalt samples compared to control samples. The interlaxyers used are: Sand asphalt interlaxyer, cement-stabilized baxse interlaxyer, reclaimed asphalt pavement (RAP) interlaxyer and bitumen-stabilized RAP interlaxyer. Laboratory samples were prepared in three laxyers, including the underlying cracked laxyer, interlaxyer and the overlay, and control samples were prepared in two laxyers, including the underlying cracked laxyer and the overlay. Three modes were considered for cracking location: middle cracks, dual cracks and lateral cracks in the underlying cracked laxyer. The purpose of this study was to investigate the effect of interlaxyer type, loading rate and crack location on asphalt mix fracture parameters. The results showed that between four interlaxyers used, bitumen-stabilized RAP interlaxyer performed better and the fracture force in the samples with bitumen-stabilized RAP interlaxyer is higher than other samples But 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.