Facilities Technology Application Tests; Concrete Repair

The Office, Chief of Engineers, through the Facilities Technology Application Tests Program, requested that the US Army Engineer Waterways Experiment Station demonstrate some of the latest technology in the use of polymeric systems for repairing concrete. Two sites at Fort Bragg were chosen for repair, a water tower and a multistory building. The six concrete footings around the base of the water tower contained numerous cracks, with some spalling and delaminated areas. One of the footings was severely scaled. The concrete balconies and support columns of the building contained numerous spalls and cracks. The cracks and delaminated areas in the footings were repaired by pressure injection of epoxy resin. The severely scaled footing was repaired by overlaying with freshly hardened concrete. The spalls were repaired with a latex-modified concrete. The spalls located on the balconies and columns of the multistory building were repaired using an epoxy-resin paste and a latex-modified concrete. The cracks were sealed with a one-component polyurethane. The concrete roof decks of two water storage tanks at Fort Ord were repaired. Both roof decks had exhibited the same problem; the concrete around the steel reinforcement had started to spall due to corrosion of the reinforcing steel, and some cracking of the roof deck was apparent. The roof decks were repaired by removing all of the unsound concrete and patching these areas with a polyester concrete. The entire roof was then cleaned and sealed with a polyester sealer followed by overlaying with a thin (3/8-in.) coating of the polyester concrete. The old joint sealant material was removed and replaced with a new joint sealant and new air vents were intalled.