Shallow deck repairs are notorious for exhibiting poor performance. One common cause of early failure is debonding between the

repair

material and the substrate. Repair material applied over large areas but in thin applications tend to build up very high stresses at the bond line, leading to premature failure. To remedy this the Contractor should excavate below the top layer of steel, which serves two purposes. First, the reinforcing cage provides a mechanical tie for the

repair

material to the rest of the deck. Second, it helps to prevent overly thin applications that have little chance of performing well.

Another common cause of premature failure is that partial-depth repairs are often implemented when full-depth would have been more appropriate. The deck soffit should be inspected at partial depth repair locations looking for areas of distress that could be weak and fail when the upper surface is being removed. Partial-depth repairs are typically easier to perform because they do not require installation of formwork or road closures under the bridge. Bridge deck distress oftentimes progresses full depth, as evidenced by cracking in the deck soffit. If map pattern cracking is visible, or if there is widespread cracking with efflorescence and rust staining, then full depth repairs should usually be implemented in lieu of partial-depth.

Intended partial-depth deck repairs can unintentionally become full-depth repairs if the Contractor utilizes equipment too heavy for the application. Contractors should not use equipment larger than necessary to perform the required demolition work, and must stay within the applicable limits outlined in the “Surface Preparation” item below, unless specifically allowed otherwise by the Engineer. No additional compensation for full depth repairs caused by contractors operations will be made.

While rapid strength gain is beneficial for returning a bridge to service, it typically has detrimental effects for the repair material.

Short duration

curing of the cementitious material can prevent even distribution of the hydration products. Also, early return of service induces stresses into concrete that can create microcracking and other defects even when the compressive strength is high.

Because deck repairs must usually be performed quickly, Engineers and Contractors often select rapid methods even when they are not necessary. It is imperative that, when feasible, slower-hydrating materials and longer curing cycles be utilized. The faster the return to service, the shorter the anticipated service life of the

repair

.