About the research
The Iowa Department of Transportation (DOT) has been using concrete overlays on its bridge decks since the 1970s to restore the concrete deck surface and to lengthen the service life of the bridge deck. The bridge deck overlays inhibit chloride and water intrusion into the bridge deck and have proven very effective as maintenance treatment on Iowa bridges. Bridge deck overlays typically last 15 to 20 years before delamination at the bond interface requires repairs to or replacement of the overlay. The delamination of the overlay is often repaired by Iowa DOT maintenance staff by injecting the deck overlay cracks and voids with epoxy. Anecdotal observation by the Iowa DOT field staff suggests that the epoxy injection process can delay repair of the overlays by another five to ten years, but currently there is no documentation to substantiate this. The process for epoxy injecting bridge deck cracks and delaminations is also not well documented resulting in wide variations in materials, equipment, and procedures used in the various districts. Annually, there is a need to perform this treatment on 120-180 Iowa DOT structures. Currently, this work is only performed by the Iowa DOT bridge crews since there are not adequate specifications for contract treatment. Due to the narrow temperature range in which this treatment can be applied, and the work load of the Iowa DOT bridge crews, it would be beneficial to have the ability to contract for bridge deck epoxy injection when necessary. The objectives of this project will cover three main focus areas: (1) determination of the effectiveness, durability, and typical service life of epoxy injection of delaminated bridge decks; (2) an evaluation of the current state of the practice in the epoxy injection industry; and (3) development of procedures and specifications for epoxy injection.