@article{cho_karshenas_tayebali_guddati_kim_2017, title={A mechanistic approach to evaluate the potential of the debonding distress in asphalt pavements}, volume={18}, ISSN={["1477-268X"]}, DOI={10.1080/10298436.2016.1149837}, abstractNote={Abstract The debonding distress in asphalt pavement structures is a critical problem that affects the performance of asphalt concrete pavements. It occurs at the layer interface due to the poor bond quality between adjacent asphalt concrete layers and/or when stresses at the layer interface exceed the strengths of the material at the interface. The debonding of the adjacent layers, especially the top surface layer of an asphalt pavement, is a contributing factor to the premature cracking of pavements. Hence, the debonding distress can lead to a reduction in the life of the pavement. This paper presents an analytical and experimental framework to evaluate the potential for debonding at the layer interface of asphalt concrete pavements. Computational analysis was performed to determine the critical stress and strain states in layered asphalt pavements under moving vehicle loads using the Layered ViscoElastic pavement analysis for Critical Distresses (LVECD) computer program developed at North Carolina State University. This computational analysis enables a greater understanding of the critical stress that is involved in debonding and the ways that such stress is affected by pavement design parameters and environmental conditions. In addition, a prediction model was developed that can determine the shear bond strength at the interface of asphalt concrete layers with different tack coat materials at various temperatures, loading rates and normal confining stresses. The systematic and mechanistic framework developed in this study employs the maximum shear ratio concept as a shear failure criterion and provides a tool to evaluate the effects of various loading, environmental and pavement factors on the debonding potential of asphalt pavements. The overall advantages of the mechanistic framework and approach using the LVECD analysis tool will help lead to better understanding of the debonding mechanism, proper selection of the tack coats, and economic benefit in highway pavement maintenance and rehabilitation costs.}, number={12}, journal={INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING}, author={Cho, Seong-Hwan and Karshenas, Afshin and Tayebali, Akhtarhusein A. and Guddati, Murthy N. and Kim, Y. Richard}, year={2017}, pages={1098–1110} }
 @article{karshenas_cho_tayebali_guddati_kim_2014, title={Importance of Normal Confinement to Shear Bond Failure of Interface in Multi layer Asphalt Pavements}, ISSN={["2169-4052"]}, DOI={10.3141/2456-17}, abstractNote={Several direct shear test devices are used to evaluate the shear bond strength of tack coat materials in interlayer bonding in asphalt pavements. Some devices have the capability of evaluating strength in direct shear with normal confinement, whereas other devices do not have that capability or use passive confinement to evaluate the interlayer bond strength. The literature indicates that interlayer bond strength increases with the application of normal confinement. However, the question remains as to the level of normal confinement, if any, that should be used in direct shear testing to evaluate the interlayer bond strength for specification acceptance or design. This study presents a methodology to interpret laboratory bond strength test results in relation to the state of stress at the layer interface in a representative pavement section. The results confirm the importance of normal confinement for shear bond strength evaluation and provide guidance for the selection of the appropriate level of normal confinement.}, number={2456}, journal={TRANSPORTATION RESEARCH RECORD}, author={Karshenas, Afshin and Cho, Seong-Hwan and Tayebali, Akhtarhusein A. and Guddati, Murthy N. and Kim, Y. Richard}, year={2014}, pages={170–177} }