From the moment it is first cast, concrete is under attack from environmental factors - carbonation of concrete, ingress, chlorides, building movement, cracking and damage to concrete surfaces through abrasion. These factors reduce the concrete's natural ability to protect steel reinforcing, resulting in corrosion of the reinforcing. As steel corrodes it expands, causing the surrounding concrete to spall and fall off, endangering both property and passersby. This degeneration is known as "Concrete Cancer".
Repair of concrete spalling (cancer) requires specialised techniques, skills and materials. In some States a contractor's licence for concrete repairs is required. It is critical to identify the cause of the corrosion before the correct repair procedure can be established. Simply patching damaged areas can result in the corrosion being transferred to the adjacent area, which subsequently spalls.
Opat's treatment includes:
- Establishing the cause of the corrosion
- Excavation of the deteriorated area
- Treatment to halt the corrosion process
- Reinstating the concrete
- Protecting against future corrosion