The spalling concrete (concrete cancer) was broken out by the contractor exposing the rusting steel enforcement. The steel is inspected to ensure that all the rusting steel has been uncovered. Often this zone extends beyond the limits of the spalled concrete. Once the extent of the rusting has been determined then the repair process can start. Initially the steel needs to be assessed for its structural strength if too much of the steel has corroded it may be necessary to add additional steel reinforcement.
Generally the process involves grinding back the steel to clean bright metal then coating the prepared steel with an anti-rust material. The concrete is then reinstated using low shrinkage cement-based specialised repair mortars. The concrete is then coated with a suitable protective paint system.
In coastal regions where the concrete is exposed to an aggressive marine environment additional well established methods can be used to improve the durability of the repairs and add life to the structure. Often concrete repair works are undertaken by tradespersons without proper investigation or detailed testing of the concrete. This is not recommended and can often lead to inappropriate and unsatisfactory outcomes such as premature failures of the repairs.
Prior to appointing a remedial contractors it is essential to obtain independent professional advice . This usually involves on-site investigations leading to the reporting, recommendations and the specification of appropriate repair strategies and materials.
Properly specified and supervised concrete repairs will ultimately provide durable long-term and cost effective solutions.