It has been observed in experiments that crack propagation in concrete is influenced by time- dependent mechanisms, not only for dynamic cases but also in quasi-static load regime, where inertia and wave effects are negligible. Those mechanisms introduce a time…
It has been observed in experiments that crack propagation in concrete is influenced by time- dependent mechanisms, not only for dynamic cases but also in quasi-static load regime, where inertia and wave effects are negligible. Those mechanisms introduce a time scale, due to the rate of loading and/or load duration (sustained load). The specific fracture energy and the peak load were observed to undergo increases as the loading rate increases. Accordingly, to study this rate effect, we develop a viscous-cohesive law en- dorsed with a viscous term dependent on the crack opening rate in a finite element smeared-crack-tip frame- work. The model is then adopted to simulate experimental results of prismatic HSC notched beams, tested in -5 1 three-point bend (TPB) configuration, where five loading rates (ranging from 10 mm/s to 10 mm/s) were employed for each set of specimens. Experimental observations are discussed and compared with numerical results obtained by the developed viscous-cohesive model. It seems that numerical simulations shows good resemblance with experiments, particularly for peak load. The model has been used also to perform a para- metric study, pointing model trends on peak load and fracture energy.