Pavement performance prediction is essential for developing durable asphalt mixtures that meet long-term service requirements. With growing interest among transportation agencies in maximizing the use of recycled asphalt materials (RAM) to promote sustainability and cost-effectiveness, challenges persist in ensuring adequate durability of high-RAM mixtures. This study, conducted as part of the NCHRP Project 09-65, aimed to enhance RAM utilization while maintaining performance standards related to cracking resistance and durability. Six robust asphalt mixtures—representative of two distinct climatic zones and designed using various high-RAM mitigation strategies—were selected based on their performance in laboratory assessments. These mixtures were evaluated using two mechanistic pavement modeling approaches: a fracture mechanics-based cohesive zone model and a continuum damage mechanics-based FlexPAVE™. A representative pavement structure of the Federal Highway Administration’s Pavement Testing Facility and laboratory test results of mixtures formed the inputs for the models. Results from both modeling approaches confirmed that RAM mitigation strategies such as the use of recycling agents, polymer-modified asphalt, and reduced RAM binder availability can significantly affect early- and long-term resistance to cracking. Although performance prediction and rankings differed slightly between the two pavement modeling methods, the combined approach offers a mechanistically grounded framework for evaluating and optimizing high-RAM asphalt mixtures for durable pavement structure.
Kommidi et al. (Fri,) studied this question.