One of the emerging solutions to enhance the durability of asphalt pavements is the use of a French asphalt mix known as “High-Modulus Asphalt Concrete (HMAC).” This mix uses a hard asphalt binder, high binder content (about 6%), and low air voids content as compared with Superpave mixtures. The key objective of this study was to develop a cost-effective HMAC mixture using crumb rubber and local materials in Louisiana. To achieve this objective, four HMAC mixtures were prepared using two asphalt binders (PG 82-22 and PG 76-22 plus 10% crumb rubber) and two Reclaimed Asphalt Pavement (RAP) contents (20% and 40%); additionally, a conventional Superpave mixture in Louisiana was prepared as a control mixture. The laboratory performance of these five mixtures was evaluated in relation to workability, dynamic modulus, rutting resistance, and cracking resistance. The AASHTOWare Pavement ME Design software was also used to estimate the long-term field performance of these mixtures. Results indicated that the HMAC mixture prepared with 10% crumb rubber and 20% RAP successfully met the French mix design specifications for HMAC and LaDOTD specifications. This HMAC mix outperformed the control Superpave mix in relation to dynamic modulus, rutting resistance, and cracking resistance. Additionally, this HMAC mixture can reduce the required asphalt thickness by 1.5 or 2 in. based on traffic level. The cost-effectiveness analysis indicated that this HMAC mixture was more cost-effective than conventional Superpave mixtures in Louisiana. In addition, this mixture is environmentally friendly as it can reduce the disposal of scrap tires in landfills.

The objective of this study was to develop a new generation of ultraviolet (UV) light-activated self-healing polyurethane prepolymer modified asphalt binder using a reactive approach and to optimize the production parameters. Rheological tests were conducted on the prepared binder blends to evaluate the effect of the modification on rutting and fatigue cracking. The effect of the modification on asphalt mixtures was also evaluated using a self-healing experiment and various mechanical laboratory tests. The formation of urethane bond was confirmed using Fourier transformed infrared spectroscopy (FT-IR). Rheological test results of the modified binder demonstrated an increase in the high-temperature grading, while no significant effect was observed on the low-temperature grade. Self-healing testing of the asphalt mixtures showed that mixtures with 10% polymer and continuous exposure to UV light exhibited the highest crack healing rate. Loaded Wheel Tracking (LWT) results showed an improvement in rutting resistance of the mixtures prepared with polymer. In addition, Semi-Circular Bending (SCB) test results showed an improvement in the cracking resistance with 5% polymer. An increase in high-temperature grade was also observed for the extracted binders from the prepared asphalt mixtures. Multiple Stress Creep Recovery (MSCR) test results of the extracted binders showed an improvement in the elastic behavior and rutting resistance with an increase in polymer content. Furthermore, the extracted binders from aged mixtures showed an improved fatigue performance with the increase in polymer content.

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