International Journal of Civil, Mechanical and Energy Science (IJCMES) [Vol-5, Issue-5, Sep-Oct, 2019] https://dx.doi.org/10.22161/ijcmes.5.5.1 ISSN: 2455-5304 www.ijcmes.com Page | 1 A Comprehensive Review on Reflective Cracking: Concept, Mechanism, and Laboratory Performance Tests Amirhosein Abedini Department of Civil Engineering, College of Engineering, University of Zanjan, Zanjan, Iran Abstract— Asphalt overlay is one the common rehabilitation alternative to mitigate a deteriorated flexible or rigid pavement. In such case, the cracks from existing pavement rapidly propagate through the asphalt concrete overlay, which makes this solution as a less durable alternative for rehabilitation purpose. The appearance of existing cracks or joint from underlying pavement through the surface of new overlayed bituminous surface is commonly referred as reflective cracking. This cracking usually appears in the early age of overlay serviceability. There are two main roots of reflecting presences cracks though new surface: traffic and environmental loading. Many studies have been done to understand the mechanism of each loading and its contribution to the reflective cracking initiating and propagation process. There is not a complete solution for preventing of such cracks in AC overlay yet, while many types of research concentrated on the retardation of reflective cracking in the AC overlay. In this review, the significant factors involved in initiating and propagation process of reflective cracking were reviewed and discussed, and then the mechanism of two primary external loading was explained. The finding showed that incorporation of an interlayer effectivity enhances the reflective cracking resistance. And also, modification of used asphalt mixture, overlay thickness, using stress relieving interlayer and incorporation of stress absorbing interlayer have an effective influence on retardation of reflective cracking in AC overlay. Keyword— Composite pavement, Asphalt overlay, Reflecting cracking, asphalt pavement. I. INTRODUCTION Asphalt mixture is one of the widespread construction material used in many countries (Mallick and El-Korchi, 2009), recently different researchers, because of the environmental issues, are paying attention to the impacts and environmental side effects of producing asphalt and concrete materials (Daghighi et al., 2017; Nahvi et al., 2018; Haghiri et al., 2018). Over time concrete overlay are deteriorated by external entities such as de-icing salt during winter, which although application of new technologies can minimized the negative effects on the concrete overlay but it is not always applicable and need relatively huge capital cost (Habibzadeh- Bigdarvish et al.,2019). Because of viscoelastic behavior of asphalt binder through asphalt concrete composition, many phenomena will happen though service life of pavement which leads it most prone for a wide array of distresses(Notani&Mokhtarnejad, 2018; Daghighi and Nahvi, 2014).There is a growing concerns regarding the deterioration of infrastructure, and the condition assessment is always a challenge (MalekMohammadi et al., 2019;MalekMohammadi et al., 2019). However, one the most common mitigation treatment for rehabilitation purpose of a deteriorated pavement is pacing an asphalt concrete overlay, which it is a quick and cost-effective alternative to enhance the structural and functional conditions of an existing roadway. When HMA overlays are placed over jointed or harshly decayed rigid or flexible pavements, the existing cracks and joints in the underlying pavement system can reflect through the surface of the newly placed HMA overlay is called as reflective cracking. Mallick and El- korchi(2009) described the reflective cracking as exhibited cracks in AC overlay, which its source can be addressed in the underlying pavement structural and functional conditions. Penman and Hook (2008) defined it as an accelerate crack propagation process from the bottom layer of the composite pavement, with a different progressive rate, upward the new pavement surface which its rate highly depends on the environmental and traffic loading.Shalaby and Frenchette(2000) named it the unanticipated occurrence of cracks on overlays at locations and orientations that