TENSILE BOND TESTING OF CONCRETE REPAIRS

The development and maintenance of a sound bond is an essential requirement of a concrete patch repair. Tensile bond tests are increasing in popularity as a means of measuring this adhesive property, both on site for quality control and in the laboratory for materials evaluation. This paper discusses the main issues relevant to tensile bond testing, namely material properties, surface conditions, geometry, loading and the effects of material mismatch. Analytical and experimental work is presented, along with the results of other researchers, with an emphasis on the core pull-off technique. The fatter is shown to be a good method for evaluating bond strength provided that appropriate precautions are taken to minimize the influence of flaws and stress concentrations, and that the effects of mismatch in repair and substrate properties (particularly modulus, shrinkage and thermal expansion) are fully understood.