Steel rebar

The affordable steel rebar is a readily available, widely used construction material that is suitable for a variety of building and construction applications. The main weakness, however, is that the steel reinforcement has a potential to corrode, resulting in staining, cracking and failure of the surrounding concrete.

Why galvanize steel rebar

Hot dip galvanized coatings have been used globally to efficiently protect steel rebar for many years. An increased corrosion resistance allows for greater tolerance on concrete quality and coverage. There are at least five  reasons why you should galvanize steel reinforcement:

  1. To prevent corrosion of steel rebar before being embedded in concrete. The hot dip galvanized coating is corrosion resistant and prevents corrosion of the reinforcement before it is embedded in concrete.
  2. The galvanized coating corrodes more slowly than steel in concrete.
  3. The possible corrosion products formed do not create internal stresses which might lead to spalling or delamination. With uncoated reinforcement corrosion products have a large volume causing tensile stresses which lead to disbondment of the reinforcement and cracking of the concrete.
  4. The coating is robust, more difficult to damage and provides sacrificial protection preventing under-cutting by rust.  Zinc is anodic to steel,  which means that at any break in the coating, the surrounding  zinc will corrode preferentially and electrochemically protect the adjacent exposed steel from corroding. The coating is metalurgically bonded to the steel, making it more robust and difficult to damage than alternative coating systems.
  5. Galvanized steel rebar extends the maintenance-free life of a concrete structure and greatly improves its overall lifecycle cost.

Steel Rebar

Applications of galvanized steel rebar

Steel reinforcements such as galvanized rebar and other fittings (such as bolts, ties, anchors, dowel bars and piping) have been used in a variety of structures and elements.  Galvanized steel reinforced concrete could be a cost effective engineering decision, especially in this particular circumstances:

  • transport infrastructure, including bridges, decks,  road surfaces and crash barriers;
  • light weight precast cladding elements and architectural building features;
  • surface exposed beams and columns, and exposed slabs;
  • prefabricated building including units such as kitchen and bathroom modules and tilt-up construction;
  • immersed or buried elements subject to groundwater effects and tidal fluctuations;
  • coastal and marine structures;
  • high risk structures in aggressive environments.

There are many examples around the world where galvanized steel rebar has been successfully used in a variety of types of reinforced concrete steel buildings, structures and general construction, including:

  • steel reinforced concrete bridge decks and pavements;
  • cooling towers and chimneys;
  • coal storage bunkers;
  • tunnel linings and water storage tanks and facilities;
  • docks, jetties and offshore platforms;
  • marinas, floating pontoons and moorings;
  • sea walls and coastal balustrades;
  • paper mills, water and sewage treatment works;
  • processing facilities and chemical plants;
  • highway fittings and crash barriers;
  • concrete lamp posts and power poles.

Steel rebar standard

The implementation of thus standard for galvanized rebar will greatly enhance the performance of many concrete structures built across the UK and Ireland. The importance of correctly protecting steel reinforcement should not be under estimated.

In December 2018, a European standard, EN 10348-2:2018 ‘Steel for the reinforcement of concrete – Galvanized reinforcing steel and steel products‘ was published. This standard allows for easy specification of hot dip galvanized reinforcement and provides details on the type of reinforcing steel and/or steel product to be galvanized, especially steel within the scope of EN 10080. Coating thickness requirements for galvanized reinforcement supplied to EN 10348-2:2018 are given in table 1.

Galvanized reinforcement often achieves coating thicknesses in excess of those indicated in table 1.

Steel Rebar

Read about steel rebar standard in our magazine