The presence of moisture beneath the pavement surface is a matter of great concerns as it is responsible for significant distresses such as asphalt concrete (AC) stripping, fatigue cracking, rutting, and poor durability of asphalt mixes. The objective of this study was to evaluate and recommend an asphalt mixture design that would provide superior performance against AC stripping and cracking. To achieve this objective, a laboratory test factorial was developed to evaluate the use of nanomaterials, emerging anti-stripping agents, warm-mix asphalt technologies, and adhesion promotors. In the experimental program, the modified Lottman test (AASHTO T 283) and the Indirect Tensile Asphalt Cracking Test (IDEAL-CT) test were used as performance indicators of moisture damage resistance and cracking susceptibility. Results were analyzed statistically to identify and quantify the effects of the design variables and selected additives on the performance, moisture damage resistance, and durability of asphalt mixes. Based on the cracking test results, a superior cracking resistance performance was observed with Zycotherm®, irrespective of the mix type. AD-here® had the lowest average cracking indices for both mix types, which suggests that it would not function as good as the other additives in terms of cracking resistance. Overall, Stone Matrix Asphalt (SMA) mixes showed greater cracking resistance than the dense-graded mixture, which may have been a result of the RAP material used in the dense-graded mix and its lower asphalt binder content. In terms of moisture resistance, both nanomaterials (Graphene Nanoplatelet [GNP] and Nanoclay) did not perform well as they did not meet the minimum required tensile strength ratio (TSR) criterion. Overall, nanomaterials showed the lowest TSR values in both mix types suggesting that their effectiveness against moisture-induced damage may not be as good as warm-mix additives. In addition, warm-mix additives were expected to show enhanced performance in terms of moisture resistance as compared to the other additives evaluated in this study.
Elseifi, M., Hossain, Z., Sarkar, M., Abohamer, H., & Oyan, M. (2023). A New Generation of Dense-Graded Asphalt Mixtures with Superior Performance against Stripping and Moisture Damage. Retrieved from https://repository.lsu.edu/transet_data/151