Moisture effects on the bond strength of FRP-masonry elements

Moisture exposure has been observed to be one of the degrading environmental agents which affect the durability of the FRP-strengthened elements by changing the constituent material or bond properties. This paper presents the experimental investigation on the effects of moisture on the pull-off bond strength of GFRP-strengthened brick specimens. The specimens have been prepared following the wet lay-up procedure and exposed to constant moisture level of 100% R.H. at 23 C for eight weeks. The degradation in the bond performance has been investigated by performing pull-off tests on the conditioned specimens after four and eight weeks of exposure. The reversibility of the bond degradation has been also studied by storing some specimens in the laboratory conditions for one week after conditioning and before performing the pull-off tests. Comparative analysis has been performed and the main results are presented and discussed.