Creep-Damage Coupled Effects: Experimental Investigation on Bending Beams with Various Sizes

The serviceability of concrete structures is a problem in which creep and damage are coupled. In this paper, we present experimental investigations on concrete that involve tertiary creep. We consider residual capacity tests on notched bending beams and investigate the evolution of size effect due to basic creep. In these experiments, beams are first subjected to a constant load, at a given ratio of the maximum capacity during 90 days. They are then loaded up to failure and their residual capacity is obtained. During the creep phase, acoustic emission is analyzed and it shows that damage develops under creep. The comparison between the size effect test results with and without creep exhibits variations of the fracture properties of the material. The fracture energy and the size of the fracture process zone decrease when creep occurs prior to failure. These results, which include size effect fracture tests, may serve for the development and validation of coupled creep-damage models.