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Publication Number: FHWA-HRT-11-060
Date: November 2011

 

Multiple Corrosion-Protection Systems for Reinforced Concrete Bridge Components

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FOREWORD

Eleven systems combining epoxy-coated reinforcement (ECR) with another corrosion-protection system were evaluated using rapid macrocell, southern exposure, cracked beam, linear polarization resistance, and field tests. The systems included bars that were pretreated with zinc chromate to improve the adhesion between the epoxy and the reinforcing steel, two epoxies with improved adhesion to the reinforcing steel, one inorganic corrosion inhibitor (calcium nitrite), two organic corrosion inhibitors, an epoxy-coated bar with a primer containing microencapsulated calcium nitrite, three epoxy-coated bars with improved adhesion combined with the corrosion inhibitor calcium nitrite, and multiple-coated (MC) bars with an initial 50-µm (2-mil) coating of 98 percent zinc and 2 percent aluminum followed by a conventional epoxy coating. The systems were compared with conventional uncoated reinforcement and conventional ECR.

The results presented in this report indicate that the coated bars provided superior corrosion protection to the reinforcing steel. In addition, bars with damaged coatings initiated corrosion at several times the chloride contents within concrete and typically corroded at rates two orders of magnitude less than conventional reinforcement. Limited additional protection was achieved using bars with primer coating, MC bars, and concrete containing calcium nitrite and one of the organic corrosion inhibitors, although the latter resulted in reduced compressive strength and reduced resistance to surface scaling.

Jorge E. Pagán-Ortiz
Director, Office of Infrastructure
Research and Development

 

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