The importance of corrosion testing & analysis for public safety

St. Philip Neri Church in Liverpool  was suffering from loose/displaced exterior masonry due to the expansive corrosion of steel reinforcement in the concrete arch beams.  Displaced masonry at height presented a serious health and safety issue due to the risk of objects falling into public areas.

CPT Testing

CPT was asked to assess the extent and type of corrosion occurring. The targeted concrete corrosion testing included a steel corrosion potential survey to locate corroding sites, 10 carbonation break-outs to assess the depth of carbonation and 30 chloride dust samples to assess the penetration of chloride salts into the concrete cover at different locations.

The testing showed that the low concrete cover to the reinforcement and un-washed sand in the mortar had contributed to both carbonation and chloride induced corrosion of the reinforced concrete arches. This had led to acute sectional loss of the shear link steel and the displacement seen.

CPT Bespoke Solution

Following the analysis of testing results, a bespoke corrosion mitigation solution was designed by CPT for the engineer. The installed system will provide maintenance-free corrosion protection for 25+ years and has allowed the exterior aesthetic appearance of the church to be maintained.

What was unique about the project?

• The quick turn-around required
• The nature of the structure
• At first it wasn’t obvious where the chloride contamination had come from as the structure is more than a mile from the sea and the testing revealed that the chlorides were not cast-in.