The Ohio State University football stadium was last repaired extensively in 1948, leaving unsightly dark, irregular patches. Numerous stains, spalling concrete, and exposed steel reinforcement called for further repair of the concrete facing. Most of the precast cornices and all the precast window grilles were in an advanced state of deterioration due to freeze-thaw damage with many pieces already having fallen to the ground. Cored samples of the concrete surface in several locations indicated a depth of carbonation in the concrete ranging from one-eighth to one and one-half inches. Orange streaks also stained the exterior of the stadium concrete.
To begin repair work, all surfaces were cleaned by sandblasting contained by a water halo. Workers contained loose concrete and concrete covering corroded steel, then replaced the concrete. More than 1,500 patches covering about 4.5 percent of the concrete surface were required. Within the concrete patches, workers painted exposed steel with an alkyd zinc-dust primer. Flat bars with rust on the inside surface were removed and replaced with new bars welded at each end. Workers replaced deteriorated precast concrete and then sealed 186,000 square feet of concrete surfaces on the exterior of the stadium with a mineral-spirits-based, silane-siloxane, hydrophobic compound at a rate of about 100 square feet per gallon. Minor ancillary work was also performed, including widening and resealing existing vertical expansion joints at 60 feet on center, replacing a few windows, and repairing and coating stucco areas.
