Contents lists available at ScienceDirect Geotextiles and Geomembranes journal homepage: www.elsevier.com/locate/geotexmem Investigations on fracture characteristics of geosynthetic reinforced asphalt concrete beams using single edge notch beam tests Nithin Sudarsanan a,* , Rajagopal Karpurapu b , Veeraragavan Amirthalingam b a North Carolina State University, Department of Civil, Construction and Environment Engineering, Raleigh - 27606, United States b Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, India ARTICLE INFO Keywords: Geosynthetics Natural geotextiles Single edge notched beam test Fracture energy Reflective cracking ABSTRACT Reflective cracking is a major cause for premature deterioration of asphalt pavements. Different varieties of geosynthetics are used at the interfaces of surface layers to control the reflective cracks. The significant factors influencing their efficiency are the flexural strength and interfacial bonding. Fracture energy that leads to de- velopment of cracks and their propagation can be investigated by single-edge notched beam (SENB) tests with sufficient accuracy. Double layered asphalt samples were extracted from pavement sections purposely built as part of this investigation for conducting quasi-static SENB tests. The goal of this paper is two-fold (a) to present a methodology for conducting SENB tests to measure the fracture properties of geosynthetic reinforced samples at temperatures of 10 °C, 20 °C and 30 °C and (b) evaluation of the flexural and the fracture characteristics of unreinforced and geosynthetic reinforced samples. The geosynthetic reinforcement did not show much im- provement of the Asphalt Concrete (AC) in the pre-cracking phase but slowed down the crack propagation. The failure pattern of reinforced specimens has changed from quasi-brittle to ductile. An equation is proposed to predict the crack initiation force of SENB sample knowing the bond strength of the corresponding reinforced AC layers at their respective temperature. 1. Introduction A typical rehabilitation practice to improve the structural capacity, ride quality, and skid resistance of the deteriorated asphalt pavements in service is to install a thin AC overlay. These pavement sections are likely to exhibit high-stress concentration near the tip of existing cracks under traffic loads causing the formation and propagation of cracks through the new overlay. These cracks are termed as reflective cracks which cause premature failure of asphalt overlay (Lee, 2008). The in- flux of water through these cracks accelerates the rate of deterioration (Cleveland et al., 2003). The concept of fracture mechanics helps in understanding the mechanism of cracking based on the failure modes in the asphalt layer (Baek, 2010). Fracture mechanics defines three modes of failure based on the direction of loading over the crack plane. Mode I (opening mode) defines the application of principal loading normal to the crack plane, and the crack propagates in a direction perpendicular to the direction of the crack plane. Modes II and III are the results of the application of the principal load parallel to the crack plane. Mode II cracks occur in an in-plane shear direction while Mode III is observed in an out-of-plane shear direction. The actual failure mechanism may be a combination of these three modes (Anderson, 2005). The primary causes for cracking in AC pavements are temperature and traffic loading. Thermal cracks belong to Mode I type of fracture. Traffic loading aggravates the Mode I cracking process. The thermal gradient developed, and pure bending under traffic loads generates varying horizontal strains along the pavement section. These strains lead to accumulation of stresses around a joint/crack. Once these stresses exceed the fracture energy of the AC mixes, the propagation of crack is initiated at the weak point within the pavement layer. Mode II cracks usually occur in composite pavements. The differential shear movement in a vertical plane above a joint/crack under traffic loading can result in Mode II fracture. Mode III fracture is rarely observed (Baek and Al-Qadi, 2006; Nithin et al., 2015). Pavement reinforcement is used as a rehabilitation method to retard these deterioration phenomena. Among the extensive range of re- inforcing products available in the market, geosynthetics are a pro- mising option. They allow an extension in pavement service life by improved tensile properties of the reinforced asphalt system, leading to a more cost-effective maintenance process (Shukla and Yin, 2004). Geosynthetic products are placed at the interface of AC layers to control the reflective cracks. However, inadequate bonding at the interface may limit the efficiency of reinforcement in controlling the crack https://doi.org/10.1016/j.geotexmem.2019.103461 * Corresponding author. E-mail addresses: nithinsudersanan@gmail.com (N. Sudarsanan), gopalkr@iitm.ac.in (R. Karpurapu), aveeraragavan@gmail.com (V. Amirthalingam). Geotextiles and Geomembranes xxx (xxxx) xxxx 0266-1144/ © 2019 Elsevier Ltd. All rights reserved. Please cite this article as: Nithin Sudarsanan, Rajagopal Karpurapu and Veeraragavan Amirthalingam, Geotextiles and Geomembranes, https://doi.org/10.1016/j.geotexmem.2019.103461