Lifetime of concrete dam models under constant loads

This paper presents the results of crack creep tests on three dam models (240 cm high) made with three types of concrete, with maximum aggregate size equal to 3.15, 12 and 25 mm. In order to characterize the material a series of tensile tests was performed for each kind of concrete. In this way the static parameters (Young's modulus, ultimate tensile strength, compressive strength, fracture energy) and creep laws were obtained. The tests on the dam models were performed in many phases: in the last the load was kept constant in order to examine the effects of concrete relaxation in terms of Crack Opening Displacement and crack propagation. Through the Cohesive Crack model it was possible to simulate the experimental results on gravity dam models by using the creep laws obtained from tensile test. Numerical and experimental results (failure lifetime, load vs. CMOD (Crack Mouth Opening Displacement), CMOD vs. time, load vs. time, crack trajectories) were found to be in good agreement.