Damage process of concrete subjected to coupling fatigue load and freeze/thaw cycles

The coupling behaviors of concrete subject to simultaneous 4-point fatigue loading and freeze/thaw cycles were, for the first time, investigated by strain technique together with acoustic emission (AE) sensors. Damage evolution of samples is periodical under the simultaneous action, which can be divided into acceleration stage and incubation stage, respectively corresponding to freeze and thaw stage. The damage mainly takes place when temperature drops, and the rate of the temperature reduction has an evident influence on the damage evolution. The quasi-Kaiser effect was firstly found in the coupling damage evolution.