Influence of wetting–drying cycles on compressive and flexural strength of cement mortar and CFRP-mortar bond strength

When mortar is exposed to the marine environment, its mechanical properties can degrade due to weathering by seawater spray and capillary rise. This paper investigates the compressive, flexural, and pull-out bond strengths of a commercially available M3 type mortar. Mortar cube and beam specimens were used for the compressive and flexural strength tests and UPV test. Mortar beams were also retrofitted with carbon fibre polymer (CFRP) and their flexural and pull-out bond strengths were investigated. All the specimens, except the control group, were subjected to accelerated wetting and drying cycles (WDC) over a period of nine weeks, where each cycle consisted of four days of wetting in tapwater and seawater at room temperature and three days of drying at 60 °C. A notable decrease in the compressive, flexural, and pull-out strengths of the mortar specimens, along with physical degradation of the mortar, CFRP and epoxy were observed following the WDC. Correlations between flexural and compressive strengths, and pull-out and compressive strengths is proposed, which can be useful in assessing the material properties of mortar during its service life.