Numerical simulation of the early-age strain behavior of lab-scale specimens and full-scale continuously reinforced concrete pavement with expansive additives

This study investigates the potential of expansive additives (EAs) for application in continuously reinforced concrete pavement (CRCP), utilizing continuously reinforced bars in longitudinal direction. EA is expected to stabilize strain behavior and mitigate the formation of transverse cracks in CRCP. To evaluate the feasibility of the practical application of CRCP with EA, this study adopts a multiscale computational finite element method (FEM) platform, which can incorporate the EA reaction effects. The simulation and experimental results are compared for different mix proportions constituting ordinary Portland cement (OPC); OPC, fly ash, and EA; and blast furnace slag cement and EA. The strain in laboratory-scale specimens was measured outdoors. The specimens with EA showed approximately 300 µm higher strain than the OPC specimen, as of 30 days. Numerical analysis with EA reaction model could reproduce the experimental trends by inputting the appropriate EA content. The model was applied to a real-scale pavement analysis accounting for the deformation restriction from reinforced bars and bottom layers. EA significantly decreases cracking risks from drying shrinkage and thermal stress in CRCP. The results indicate that EA mitigates rebar corrosion. Thus, this study contributes significantly to the development of sustainable pavement structures.