In order to design reliable concrete structures subjected to high level loading during a long time, prediction of long term behaviour of concrete and coupling between creep and damage is important. An experimental investigation on the fracture properties of concrete…
In order to design reliable concrete structures subjected to high level loading during a long time, prediction of long term behaviour of concrete and coupling between creep and damage is important. An experimental investigation on the fracture properties of concrete beams submitted to three point bending tests with high levels of sustained load that deals with creep is reported. The specimens’ sizes were 100×200× 3 800mm as per RILEM-FMC 50 recommendations. Quantitative acoustic emission (AE) techniques were used to monitor crack growth and deduce micro fracture mechanics in concrete beams before and after creep. The influence of creep on residual capacity, fracture energy, fracture toughness, and characteristic length of concrete has been studied. The load versus the crack mouth opening displacement relationship is linear in the ascending portion and gradually drops off after the peak value in the descending portion. The fracture energy and the characteristic length increase. The sustained loading seems to give a strengthening effect to concrete, probably because of the consolidation of the hardened cement paste. But the influence of creep on the varia- tion of the fracture energy is not trivial. It seems that the chosen method is not fine enough to characterize the creep-damage coupling. So, the acoustic emission method has been applied to characterize the crack devel- opment during the three-point bending test. Results show a high amplitude level at the maximum load for creep specimens, which characterize a high consumed energy to nucleate the crack.