Best Practices for Preparing Concrete Surfaces Prior to Repairs and Overlays

One of the biggest problems impacting the long-term performance of concrete repairs and bonded overlays is cracking of the repair material and repair material debonding from the concrete substrate. There are many purposes for concrete repair, including prolonging the useful service life of a deteriorated or distressed structure or element, restoring the load carrying capacity and the stiffness, and strengthening the structure. In most cases, for the repair to be successful, monolithic action (acting as one unit) between the repair material and the substrate concrete (the composite repair system) is needed. A prerequisite for monolithic action is long lasting bond between the existing concrete substrate and the repair material. The objective of this study is to identify the key physical characteristics of a concrete substrate needed to ensure successful, long-term repairs and overlays, and to develop a “Suggested Guide Specification for Concrete Surface Preparation Prior to Repair.” To meet this objective the following tasks were performed: (1) A review of existing literature to establish fundamental factors and characteristics of the concrete substrate preparation prior to repair; (2) Summarize the results of the International Research Project, “Development of Specifications and Performance Criteria for Surface Preparation Based on Issues Related to Bond Strength” (located in appendix B and summarized in chapter 3); and (3) Based on the first two tasks, develop practical guidelines in the form of a “Suggested Guide Specification.”