Mechanical analysis of cement concrete pavement structure considering the material's tensile and compressive difference characteristics

Current cement concrete pavement design methods do not scientifically consider the significant differences between tensile and compressive moduli, resulting in deviations between analytical results and actual pavement performance. The mechanical tests for the parameters of tensile–compressive stiffness were conducted. Structural responses under coupled axle loading-temperature effects were analyed based on the bimodulus theory. Results showed that the tensile moduli (E t ) was significatly lower than the compressive moduli (E c ). The Poisson's ratios (μ c , μ t ) decrease exponentially with increasing loading rate (v) and tended to stabilize when v exceeds 0.1 MPa/s. The relationship between the tensile-compressive stiffness parameters satisfied the assumption (E c /μ c = E t /μ t ) of Ambartsumyan's bimodulus theory; A numerical model considering stress-temperature field coupling and tensile-compressive differences was established. The most unfavourable load position is located at the mid-edge of the longitudinal joint under coupled temperature-load effects, with maximum tensile stress occuring at the slab bottom beneath the wheel load centre. The temperature considerably affects both stress and deformation, with differences up to 38% and 25%, respectively, whereas axle load effect mainly affects the stress (differences up to 14%). The axle loading-temperature (positive gradient) condition was most unfavorable. Under coupling, the differences reached 30% and 25% for stress and deformation, respectively, demonstrating that temperature effects amplify the influence of tensile–compressive differences. Therefore, the bimodulus theory is of great significance for structural analysis and design of cement concrete pavements.