Location: Duquesne Electric, Cheswick, PA 

Structure: Seawall 

Problem

In September 1996, Surtreat Representative Lori Sims toured the Duquesne Light Cheswick Power Station with Nick Bauer to evaluate the condition of concrete structures both inside and outside of the plant. Consideration was given to the water pump area, the switching station, and the seawall in the coal handling area. The tower bases in the switching station showed a lot of deterioration. However, Bauer and Sims focused their attention on the advanced deterioration of the concrete seawall: the unstable condition could potentially disrupt coal-handling operations.

The seawall face had at least 15 areas where concrete was spalling and delaminated from the reinforcing steel (rebar). The rebar was corroding and in some places. This was visible to the naked eye. The weaker concrete in the seawall cap was spalling and delaminated in some areas, other areas were crumbling. Ideally, the seawall should be stable enough to support the tasks associated with coal handling. Typically, personnel are continuously climbing up and down stairs that are hinged between the wall and a work float so that they can physically cross over onto the barges to that are to be repositioned beneath the coal scooping equipment. This task is performed up to seven days a week five hours a day. Eventually, the seawall’s instability could result in a disruption to barge unloading operations.

Recognizing Duquesne Light’s policy to first allocate funds to mechanical failures that directly impact the combustion and steam generation processes. Bauer asked that our proposal to repair the wall focus on fixing the root cause of the deterioration. That is, the goal of providing a high performance, cost effective “wall stabilization” program was to supersede any budget to “make it look pretty. ”Surtreat’s Proposed Restoration and Protection Plan detailed recommendations under Cheswick Service Order 771-6-135prepared in November1996 indicated that without remediation the rebar corrosion, and in turn, the spalling and delamination would continue. And it did.

WANT TO LEARN HOW WE PREVENTED FUTURE CORROSION AND TREATED THE CURRENT CORROSION ISSUE WITH THE USE OF SURTREAT®?