Tackling Insufficient Concrete Cover Problems: What Are the Choices?

Low Concrete Cover Issues

Concrete cover refers to the distance between theconcrete surface to steel reinforcement. Theconcrete cover is critical in protecting the steelreinforcements from environment effects, therebypreventing corrosion.

With insufficient protection, steel corrode andcauses spalling concretes and deterioration of thestructure.Rectification of low concrete cover is a realchallenge. Rebuilding the concrete cover isusually impractical and costly. In majority of thecases, it would be practically difficult to hackdown and reconstruct such large extend ofproblematic concrete structures.

What Are the Choices?

To tackle the Insufficient Concrete Cover problem, Fosroc list out several practical choices. Each with its own particular benefits and merits to suit the specific project requirements without the hassle of hacking off extensive concrete:

Surface Applied Corrosion Inhibitor

Fosroc Protectosil CIT is an easy to use, surface apply corrosion inhibitor for steel reinforced concrete. The treatment can penetrate deeply into concrete substrates and reduce rates of any ongoing chloride or carbonation induced corrosion in existing concrete and will delay the onset of chloride induced corrosion in new and old concrete.

“Fosroc Protectosil CIT” would not affect the appearance of concrete, and will penetrate deeply into concrete and form protective layer around steel reinforcements, thereby slow down steel corrosion in low concrete cover concrete.

For application on insufficient cover concrete, the Fosroc Protectosil CIT penetrate and generate the passivating layer at steel reinforcements. Studies shown that it can slow down the rate of corrosion by more than 90%.

Anti-Carbonation Reinstatement Mortar

Renderoc S is a structural grade polymer modified concrete reinstatement mortar designed with extremely low permeability. It provides maximum protection against carbon dioxide and chlorides, which are the key factors in spalling concretes.

Testing has shown that a 10mm thickness of Renderoc S mortar is equal to 250mm of concrete cover, in terms of carbonation protection. This significantly prolongs the service life of an insufficient cover concrete and helps prevent spalling caused by carbonation and other corrosive elements.

Renderoc S applied as Anticarbonation reinstatement mortar for renovation project in Hong Kong.

Renderoc S applied as Concrete Cover reinstatement mortar for a building renovation project in Hong Kong.

Renderoc S as a structural grade mortar, which form monolithic bond with concrete structure. Unlike coating, it has no concerns on regular maintenance issue .

Color Anti-Carbonation Protective Coating

Dekguard E2000 is an elastomeric protective coating for concrete structure. The protective coating protects the concrete structures from attack by carbonation, chloride ion, water and oxygen.

Dekguard E2000 iselasto America and Canada accommodate fine cracks in concrete substrate .

The protective coating system applied to concrete shall providing equivalent protection to 500mm of concrete cover in terms of carbonation protection. Hence effectively prevent steel reinforcement corrosion and spalling concrete in low cover concretes.

Additionally, Dekguard E2000 provides a breathable, color coating finish with ranges of color choices.

Dekguard E2000 protects the concrete structures from carbonation attack for Heritage Preservation project in Hong Kong .