Fracture behavior of warm mix asphalt mixtures incorporating Cecabase and recycled concrete aggregate: An experimental and numerical assessment

This study investigates the fracture performance of warm mix asphalt (WMA) mixtures modified with Cecabase RT BIO10 and various recycled concrete aggregate (RCA) proportions using laboratory tests and finite element modeling. Semi-Circular Bending (SCB) tests at –15 °C under Mode I loading were performed to measure fracture toughness (KIC), fracture energy (GF, pre-peak and post-peak), stiffness, and flexibility indices. Unlike many prior studies relying on a single approach, fracture toughness was calculated through all major analytical methods and validated with ANSYS finite element simulations. Results showed that increasing Cecabase content notably improved fracture resistance, while higher RCA levels reduced mechanical properties due to the porous nature of RCA. Fracture energy analysis indicated that post-peak deformation parameters correlated more strongly with GF than stiffness indices, highlighting the importance of ductility in asphalt performance. Correlation analyses revealed tensile strength (TS) and tensile stiffness index (TSI) largely evolve independently from post-peak flexibility indicators such as flexibility index (FI), toughness index (TI), and crack resistance index (CRI). Among mixtures tested, the combination of 0.50 % Cecabase and 10 % RCA exhibited the most balanced performance with high TSI, TS, and GF values. These findings emphasize the need to optimize both additive and RCA content to enhance WMA mixtures’ mechanical integrity and sustainability. The proposed approach offers a practical and environmentally friendly framework for designing durable asphalt mixtures suited to low-temperature pavements. © 2025 Elsevier Ltd