North Carolina State University - Mann Hall

Background:

The engineering building (Mann Hall) at North Carolina State University was built in 1964 and began showing signs of distress and corrosion. Spalling of the concrete columns and along the perimeter of the building became a prevalent problem and led to structural and condition assessment. It was found in the assessment that cast in chlorides were used during the construction of the building, which over time lead to the initiation of corrosion of the reinforcing steel. The presence of chlorides in the concrete meant repairs alone would not be sufficient in addressing NCSU’s corrosion problem, which led to engineers and owners to implement a protection system.

Column after excavation for PatchGuard Connect installation

Column excavated for repairs from corrosion damage

PatchGuard Connect Anodes installed in column

PatchGuard Connect anodes installed in column for corrosion protection

Solution: For long term corrosion mitigation and maximizing the service life of the structure/repairs, the PatchGuard Connect system was selected and installed in the columns at Mann Hall. The PatchGuard Connect anodes provide protective current to the reinforcing steel and stop the electrochemical process of corrosion, despite the presence of chlorides within the concrete. The system was designed for a 20+ service life, along with monitoring stations on select columns to track system performance. Addressing and arresting corrosion, instead of dealing with the symptoms (spalling, rust bleeding, delaminations, popouts) will surely provide great economic benefit to the university while minimizing future disruption for students.