Experimental and Numerical Study of the Tensile Behavior of Dam Concrete

Tensile behavior governs the seismic safety of high concrete dams. This study integrates testing with mesoscale simulation to elucidate the tensile-failure mechanisms of dam fully graded concrete. Uniaxial tension, splitting tension, and flexural tests were performed on 450 mm-scale specimens using a 15 MN servo-hydraulic system. A two-dimensional random-aggregate model was then developed with globally inserted cohesive interfaces, and parameters were calibrated against the tests. Across ten random aggregate mesoscale models per loading case, simulations reproduced the measured responses. Predicted failure patterns matched observations, with cracks initiating along interfacial transition zones (ITZs), linking through mortar, and forming through-cracks. Quantified damage evolution revealed three stages—elastic response, ITZ crack initiation and extension, and mortar penetration—with >80% of cumulative damage localized in ITZs. One-at-a-time sensitivity analyses showed that (i) mortar tensile strength primarily controls peak strength but increases brittleness; (ii) ITZ tensile strength governs crack-initiation stress, ITZ shear strength shapes splitting-failure mode, and fracture energies mainly delay post-peak softening; and (iii) aggregate parameters exert comparatively weak influence on macroscopic behavior. The combined experimental–mesoscale framework provides mechanism-based guidance for selecting material parameters in seismic analyses, supporting performance-informed design and assessment of high dams.