Mechanical behavior of cement-stabilized macadam materials coupled with recycled asphalt pavement (RAP) and latex

Cement Stabilized Macadam (CSM) is known for its high strength but is prone to reflective cracking due to shrinkage. Recycled Asphalt Pavement (RAP) materials have gained attention for sustainable road construction, yet the relationship between RAP characteristics and interfacial bonding with cementitious materials remains unclear.Therefore, this study investigates the mechanical behavior of CSM coupled with RAP and latex. Tests including unconfined compressive strength, splitting tensile strength, compressive resilient modulus, frost resistance, and dry shrinkage were conducted. Advanced microscopic techniques such as X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM), mercury intrusion porosimetry (MIP) to elucidate the underlying microstructural mechanisms. Results showed that 30% RAP content in CSM achieved optimal mechanical performance. Latex increased unconfined compressive and splitting tensile strength by 9.95% on average and improved frost resistance, though the compressive resilient modulus decreased. SEM revealed that latex formed an elastic network that optimized the interfacial transition zone, reduced porosity, and mitigates crack propagation. This study links microstructural features to macroscopic properties, providing insights for optimizing RAP use in CSM and promoting sustainable road construction.