Effect of temperature and relative humidity on cement-bitumen treated materials produced in the laboratory using emulsion or foamed bitumen

Full-depth reclamation (FDR) is an asphalt pavement rehabilitation technique that increases the structural capacity of deteriorated pavements while reducing costs, energy consumption, and resource use, compared to a reconstruction. Despite these advantages, FDR application remains limited, primarily due to gaps in knowledge regarding its design and quality control methods. The mechanical properties of FDR mixtures vary significantly with composition, making an appropriate curing period essential for optimal performance. This study investigates the effects of temperature and relative humidity on emulsion and foamed cement-bitumen treated materials (CBTM) used in FDR applications. Three curing regimes were compared by measuring water loss, indirect tensile strength, and indirect tensile stiffness modulus at 1, 3, 7, and 28 days for both emulsion and foam mixtures. Additionally, emulsion samples underwent extended curing up to 90 days to simulate and assess the long-term effects of climatic variations on material stiffness. Results showed that curing at high temperature and low relative humidity (first regime) produced the highest mechanical properties, while an extended transition from low to high humidity (second regime) reduced performance. Simulating nighttime conditions with 12-hour cycles of high humidity (third regime) delayed mechanical development. For emulsion samples, extended curing at high temperature and low humidity after 28 days did not significantly affect stiffness, while humidity and temperature variations influenced material stiffness. These findings demonstrate CBTM’s adaptability to varying environmental conditions, offering practical guidelines to predict long-term performance based on climate, enhance durability, and reduce construction timelines for FDR-treated pavements. • Mechanical properties of foam mixtures are superior to those of emulsion in the short term. • Stiffness of foam mixtures is less sensitive to changes in humidity. • Stiffness loss caused by exposure to high relative humidity (of 100 %) is reversible. • A 28-day cure at high temperature and low relative humidity assesses the ultimate stiffness of the material.