Evaluation of Maintenance Procedures for Bridge Spalling on Parapet Walls

Parapet wall deterioration concerns the Ohio Department of Transportation as well as other transportation agencies. The spalling of parapet walls presents a danger to the traveling public, as pieces of deteriorated concrete may fall onto the road below. The current repair method is to chip off the weakened concrete using pneumatic chipping hammers. However, this process not only damages the sound concrete, but it also leaves an unprotected surface. This project implemented hydrodemolition as a means of removing spalled concrete. A hydrodemolition robot was utilized in the field to remove concrete on the interior and exterior face of a parapet wall. This method was determined as promising as it does not damage the sound concrete surface and exposed reinforcing steel, it mitigates silica dust, and it efficiently removes unsound concrete. Polyaspartic polyureas are a concrete protectant/sealant that may be rolled onto a prepped concrete surface using a paint roller. This material not only seals the concrete but may provide a reinforcing barrier that retains loose pieces of concrete. This material was used to coat several parapet walls in the field, and it was observed that three of the five polyaspartic products appeared effective in the field at providing a protective barrier. In contrast, all were equally effective in laboratory testing.