Damage and degradation mechanism for single intermittent cracked mortar specimens under a combination of chemical solutions and dry-wet cycles

The mechanical behaviors and failure characteristics of cracked mortar specimens subjected to dry-wet cycles in different chemical solutions were investigated in this paper. A non-penetrating crack with a certain inclination and length was prefabricated in each specimen by embedding a copper sheet when casting mortar and then removing it when the mortar initially set. Through our experiments, the stress-strain curve, peak strain and strength, crack position and crack orientation, failure characteristics and damage degradation mechanisms of cracked mortar specimens were measured and analyzed. To identify the degree of damage deterioration of the specimens, the damage variable was expressed in terms of changes in elasticity. The tests showed that the peak strength initially decreased and then increased with the continuous increase of the inclination angle. A remarkable weakening trend occurred in the specimens subjected to dry-wet cycles in different chemical solutions. The initial crack location, orientation and failure features of the cracked specimens were not affected by the chemical solutions and dry-wet cycles, but the crack inclination angle had very significant effect. The microcrack initiation of cracked specimens occurred earlier after dry-wet cycles than under natural condition, and the time of the microcrack extension after dry-wet cycles was longer than it was under the natural state. (C) 2019 Elsevier Ltd. All rights reserved.