Performance of recycled aggregate base using linear and non-linear prediction models

This study investigates the long-term performance of recycled and virgin aggregate base materials in flexible pavements by comparing linear and non-linear pavement structural response models. The materials included coarse and fine recycled concrete aggregate (RCA), limestone (control), and blends of reclaimed asphalt pavement with RCA. Pavement distresses, such as fatigue cracking (both top-down and bottom-up) and rutting, were predicted using the mechanistic-empirical pavement design guide methodology, where the critical structural responses were obtained using linear elastic analysis (LEA) and finite element analysis (FEA) approaches. Data from falling weight deflectometer (FWD) tests and laboratory resilient modulus (M_R) tests were also used separately, in both approaches, to study the differences between in situ and laboratory conditions. The results showed that RCAs exhibited higher stiffness and improved performance compared to limestone. LEA-based analysis produced conservative performance predictions, while non-linear FEA-based analysis offered lower distresses. Also, FWD responses suggested stiffer in situ conditions for RCA base layers, in case of both models, when compared to laboratory M_R results.