A Review of Direct Shear Testing Configurations for Bond between Fiber-Reinforced Polymer Sheets on Concrete and Masonry Substrates

The surface bond characteristics of Fiber-Reinforced Polymer (FRP) sheets have been subject to research for more than two decades. These sheets generally exhibit brittle performance during direct shear and often delaminate prematurely before they attain the full strength of the material. This paper reviews the experimental testing configurations to investigate the direct shear bond surface characteristics of FRP sheets on concrete and masonry substrates. Additionally, it summarizes the data acquisition methods and the observed behavior for surface bond of FRP sheets on concrete and masonry. This review aims to serve as a source for future experimental research studies in the field. Further, an innovative testing configuration is suggested to measure bond strength of FRP sheets on concrete and masonry surfaces in direct shear.