**4. Concluding remarks**

The acoustic emission approach has been successfully implemented to address the shortage for accurate and reliable techniques to evaluate cracking performance of asphalt pavements. In addition, the AE method has been applied for assessing the efficiency of rejuvenator-treated pavements and to evaluate and characterize virgin, short-term, and long-term asphalt binders and asphalt concrete materials. The AE technique has also been employed in different areas such as evaluating asphalt pavements containing recycled materials such as RAP or RAS, assessing the effect of cooling cycles upon the structural integrity of pavements, and characterizing the thermal cracking performance of graded, i.e., aged asphalt pavements. The promising results from aforementioned studies suggest that the AE technique can be considered as a viable approach for the assessment of asphalt pavements. Moreover, when used for preventive maintenance and rehabilitation, AE method can serve as a powerful tool in enhancing pavement sustainability. Both up-stream and down-stream suppliers and producers of asphalt concrete binders could benefit from AE technique. The up-stream supplies of polymer, chemical, and other additives (warm-mix additives, antistrip agents) could use AE for rapid assessment of low-temperature characteristics of trial formulations, and could quickly evaluate the compatibility of blended additive systems. Asphalt mixture designers could take advantage of the AE technology in order to verify binder grade selection and to optimize the amount of recycled materials used in the pavement. Finally, the pavement owners could implement AE for quality assurance of asphalt binders and asphalt mixtures, for periodic pavement condition assessments, and for the scheduling of preventive maintenance and rehabilitation, where pavement cracking is of concern.
