Concrete Substrate Preparation and Characterization Prior to Adhesion of Externally Bonded Reinforcement

The bond between externally bonded FRP reinforcement and concrete substrate is highly dependent on the quality of the surface preparation. Accordingly, accurate measurement of surface roughness could lead to the more reliable and predictable bond behavior. This paper presents the results of an experimental study aimed at investigating the effect of surface preparation on bond performance of externally applied reinforcement other than FRP. Water jetting was used as the abrading method. The quantitative assessment of surface roughness was conducted using a newly-developed laser profilometer. Samples of externally applied steel reinforced polymer (SRP) and steel reinforced grout (SRG) reinforcement were pull-off tested. Comparison to the state-of-the-art surface characterization method using plastic concrete surface profiles was undertaken, yielding a relationship between the roughness of the concrete surfaces and the roughness of the plastic models. Experimental results of this project showed that the effect of the surface roughness on the pull-off strength of the externally applied SRP and SRG reinforcement was not a key factor. This was because in the first instance failure always occurred in the concrete substrate, while in the latter it occurred in the gout layer