What are the main methods to protect rebar from corrosion according to this code?

The primary methods are: using high-quality dense concrete, applying protective coatings (like epoxy or galvanization) to rebar, using corrosion-inhibiting admixtures, and implementing cathodic protection systems (Clause 4).

Is simply increasing concrete cover enough for protection in marine environments?

While increasing cover is a primary protective measure, in very aggressive environments like marine splash zones, it may be insufficient alone. The code recommends combining it with other systems like coatings or special cements (Clause 5).

What is cathodic protection for concrete?

It's an electrochemical method where a direct current is applied to the reinforcement, making it a cathode and thus preventing it from corroding. This can be done using sacrificial anodes or an impressed current system (Clause 4.4).

Does this code provide specifications for coated bars?

This code provides recommendations. Specific requirements for products like fusion-bonded epoxy-coated bars are detailed in separate standards such as IS 13620.

IS 11843

: 1986

Recommendations for Corrosion Protection for Reinforcement in Concrete

CurrentSpecializedGuidelinesBIMMaterials Science · Coastal and Marine Engineering

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This standard provides recommendations and guidelines on various methods for protecting steel reinforcement from corrosion in concrete. It covers the principles of corrosion and details protective measures like high-quality concrete, coatings (epoxy, galvanizing), corrosion-inhibiting admixtures, and cathodic protection, particularly for structures in aggressive environments like coastal and industrial zones.

Offers recommendations for protecting steel reinforcement against corrosion in concrete, important for long-term durability.

Quick Reference Values

Maximum chloride content in cement for RCC (severe exposure)0.6 kg/m³

Maximum chloride content in cement for PSC0.1 kg/m³

Typical Dry Film Thickness (DFT) for Fusion Bonded Epoxy Coating130-300 µm

Minimum zinc coating mass for galvanized bars300 g/m²

Recommended max crack width for corrosion protection0.1 mm in severe environments

Practical Notes

Extreme care must be taken during handling, transportation, and bending of coated bars to avoid damaging the protective layer, as damage points become corrosion hotspots. Any damage must be repaired with a compatible material before concreting.

The effectiveness of any corrosion protection system is significantly enhanced by ensuring high-quality, dense, and impermeable concrete with adequate cover, as specified in IS 456.

Using coated reinforcement may affect the bond strength between steel and concrete. This should be considered in the structural design, potentially requiring increased development lengths.