VISCOELASTIC RESPONSE AND STRENGTH RECOVERY OF PAVEMENT BASE MATERIALS UNDER MOISTURE-DEPENDENT CONDITIONS

Abstract: The performance of pavement base materials under flooding conditions is crucial for the durability and resilience of road infrastructure. This study evaluates three types of base materials: two unbound aggregate bases and a crushed and shaped (C&S) material containing 4.53% binder. The effects of moisture on their mechanical and viscoelastic properties were investigated to identify which materials are more prone to strength and stiffness loss during and after flooding, as well as their recovery behavior. Laboratory testing involved resilient modulus (MR) measurements under various confining pressures, saturation levels, and temperatures. Results showed that one unbound base material was highly sensitive to saturation and exhibited a significant reduction in stiffness, while the other unbound material showed a smaller decrease. The C&S material, though widely used in practice, demonstrated distinct viscoelastic behavior influenced by both moisture and temperature. At lower temperatures, it exhibited a higher stiffness, while at higher temperatures, the binder softened, resulting in more pronounced viscoelastic effects and reduced stiffness. These findings highlight that the moisture and temperature dependent responses of base materials vary significantly, underscoring the need for targeted evaluation of base layer composition in flood-prone and temperature-variable regions. This work contributes to advancing resilient pavement design by emphasizing the combined influence of moisture and temperature on viscoelastic behavior as a critical factor in base material selection.