Moisture Content Requirements for Effective Concrete Repairs

Project ID: 2886
Principal Investigator: John Robertson
Research Topic: Repair and Maintenance
Funded Fiscal Years: 2014 and 2015
Keywords: None

Research Question

What is the optimum moisture content for the concrete substrate for different concrete repair materials to ensure successful long-term performance?

Need and Benefit

Results from research just completed show that the moisture condition of the concrete substrate can have a large impact on the success or failure of a repair.

The success of concrete repairs and overlays is lower than desired and hard to predict. Many times they crack prematurely, reducing the service life of the repair and requiring expensive repairs much sooner than originally planned. Recent surveys of operation and maintenance water management training participants showed that about 30 percent of the attendees performed some level of work on concrete repairs--most of the repairs were small, and most only lasted about 2 years.

This lab has been working for a number of years in this area, along with partners from other government agencies, universities, material suppliers, and concrete repair specialists. This problem with repairs and overlays is not unique to the Bureau of Reclamation (Reclamation), but is reflected in the repair industry as a whole. The problem is more significant to Reclamation because of the age and quality of much of our older concrete structures, making repairs even more difficult.

Contributing Partners

Contact the Principal Investigator for information about partners.

Research Products

Bureau of Reclamation Review

The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.

Moisture Content Requirements for Effective Concrete Repairs (final, PDF, 9.0MB)
By Janet White
Publication completed on September 30, 2016

This report describes results from a 4-year project designed to develop guidelines for moisture conditioning of a concrete substrate prior to a cementitious repair, which was part of a larger effort to develop guidelines for surface preparation of concrete prior to repair. Over the course of this project, a variety of slabs were prepared for an overlay repair under a variety of conditions. Bond strength tests were performed to measure the bond characteristics of the repair interface. From the test results, guidelines were developed relative to the types of materials used. In addition, findings showed that aspects of moisture conditioning deserve further study.

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Last Updated: 6/22/20