Corroded reinforcing steel is a common problem for structural concrete repair. Following industry best practices for concrete repair and rebar corrosion re-passivation will avoid future steel corrosion and maintain structural integrity. The following post outlines these procedures and includes images from a recent project completed by Restruction Corporation’s Arizona office.
Previous, poorly executed repairs allowed rebar corrosion to continue at wall top sections. Corroded steel rebar occupies more volume than the original non-corroded rebar, causing spalling in the concrete to develop. Using correct material selection and placement techniques during repair will ensure complete structural integrity and restore the concrete bond.
The first step in this repair involves removing both sound and unsound concrete to reveal the circumference of the corroded steel rebar. Remove concrete along the bar length until the corrosion product cannot be observed. Utilize abrasive blasting techniques to remove corrosion, expose new clean steel, and prepare the original hardened concrete for bonding. Apply a rebar coating to re-passivate the reinforcing steel. Selecting a pourable or pumpable low shrinkage, ready-mix concrete or pre-bagged cement-based repair material will provide a clean-formed finish. Improving the waterproofing detail to prevent water from entering the concrete pore structure will add additional durability.
Careful selection of concrete repair techniques, as well as proper application, guarantees an aesthetically pleasing and structurally sound repair.