Effects of environmental conditions on performance of polymeric adhesives for restoration of concrete structures

The effects of exposure to different environmental conditions on the bond strength between a thermosetting adhesive and concrete were investigated. In particular, the influence of temperatures higher than room temperature and the presence of water on adhesion properties were studied. The results were compared with those relative to specimens tested in ordinary conditions. The increase of test temperature caused a reduction of the bond strength irrespective of the concrete used. The effect of temperature was almost completely reversible because the bond properties were recovered when the temperature was lowered. The presence of water also caused a decrease in adhesion properties, at least to a minor extent. These conditions also affected the mechanism of failure occurring in the samples. On the basis of the obtained results, it is suggested that the environmental conditions in which the adhesive is employed be carefully examined to avoid the occurrence of unexpected failure of the bond and compromising the effectiveness of the repairing technique.