What is the Pull-Off Test in concrete repair?

The Pull-Off Test is a Quality Assurance (QA) method used to measure the bond strength of a repair material or coating to the concrete substrate. A metal 'dolly' is glued to the surface, and a machine pulls it until it detaches. The force required to break the bond is recorded in MegaPascals (MPa). A successful test usually requires the failure to occur in the concrete substrate itself (cohesive failure), proving that the bond is stronger than the concrete. This ensures our repairs will not delaminate over time.