Bond behaviour between NSM CFRP strips and concrete substrate using single-lap shear testing with cement-based adhesives

The efficiency of strengthening RC beams using the near-surface mounted (NSM) carbon fibre-reinforced polymer (CFRP) method depends on the bond between the NSM CFRP and the concrete substrate. This study presents the results of a study of the bond efficiency of NSM CFRP strips with two different CFRP strip surface types (smooth, rough) and dimensions (1.4 × 10 mm, 1.4 × 20 mm) with cement-based adhesive using single-lap shear tests. The study also contains development of a statistical model to predict the bond strength (pull-out force). It was found that the rough surface CFRP showed superior bond strength (pull-out force) when compared to the smooth surface CFRP. Moreover, there is a very good agreement between the experimental and predicted results.