Abstract: To establish a bending constitutive model for asphalt concrete beams under coupled temperature-loading rate effects, large-scale bending tests were conducted using an asphalt concrete beam testing system across multiple temperature and loading rate ranges.By integrating Duncan-Chang EB model with the temperature equivalence principle of materials based on the bending test results, a dual-parameter (temperature-loading rate) constitutive model was developed for hydraulic asphalt concrete core walls.The research findings indicated as following.At 0 ℃, the bending strength of asphalt concrete significantly increased with loading rate (from 0.90 MPa to 2.90 MPa), showing a strong positive correlation, while the critical bending strain remained rate-insensitive.Within the 10 ℃ to 20 ℃ range, bending strength continued to rise with loading rate, whereas critical bending strain exhibited pronounced strain-softening behavior under higher loading rates.The model accurately captured the mechanical response under varying temperature-loading rate combinations, with prediction errors below 8.5%.