Corroded reinforcement is the chief cause of concrete deterioration, which prompts subsequent repairs. For repairs to be sound, contractors must ensure adequate adhesion of new patch repair materials by proper preparation of exposed reinforcing steel. ICRI’s 310.1R-2008 ‘Guide for Surface Preparation for Repair of Resulting from Reinforcing Steel Corrosion’ states that exposed reinforcing steel should be free of any materials such as concrete, dirt, and corrosion products that could interfere with repair material adhesion, although a tightly bonded light rust on the rebar surface is usually not detrimental to the bond of patch materials. When it comes to tackling reinforcement surface prep and ongoing protection, CorrVerter® MCI® Rust Primer offers advantages to mitigate rebar corrosion.
Resolving existing corrosion
Many rebar coatings containing corrosion inhibitor typically require a rust-free application surface to work properly. Abrasive or water blasting and intensive labour are usually needed to ensure corroded surfaces are completely clean. This is not necessary for CorrVerter MCI, which is recommended for application on rusty or poorly prepared steel surfaces where further corrosion protection is required and good surface preparation is difficult to achieve. CorrVerter MCI is a unique formulation of chelating agents combined with a high solids waterborne latex with extremely low water vapour permeability. This fast drying, single-component primer converts surface rust into a hydrophobic passive layer and offers protection against re-rusting of metal surfaces. Reinforcement coated with the primer has similar bond strength to concrete compared with uncoated rebar.
Preventing future corrosion
CorrVerter MCI Rust Primer data reports 500 hours of corrosion resistance in salt spray testing (ASTM B-117) at only 3 – 5 mils (75-125 µm) DFT (applied at 8.7-14.5 mils [217.5-362.5 µm] WFT).
The primer offers engineers, owners, contractors, DOTs, and government agencies a convenient, low-labour option when performing repairs on heavily corroded rebar and other metal surfaces.
It converts rust quickly and provides ongoing protection without compromising bond strength.
Read the article online at: https://www.worldcement.com/product-news/08122020/cortec-provides-concrete-erosion-protection/