Alternative Reinforcement for Concrete in Corrosive Environments

Project ID: 620
Principal Investigator: Christine Daniels
Research Topic: Repair and Maintenance
Funded Fiscal Years: 2016
Keywords: None

Research Question

What alternative concrete reinforcement materials exist for use in corrosive environments? Do these materials
offer corrosion resistance without compromising the desired physical properties present in steel reinforcement?
What are the trade-offs for using the more corrosion resistant materials?

Need and Benefit

Concrete is often reinforced with steel for improved tensile mechanical properties.
Reclamation's concrete structures, such as: bridges, buildings, tunnels, and dam walls all contain reinforcing
steel for this added tensile strength. In certain environments this is not an issue, but there are highly corrosive
environments where steel reinforcement is of concern. A primary cause of degradation to steel reinforced
structures is corrosive damage to the embedded rebar.
Steel breaks down when exposed to corrosive agents such as salt and carbonation. Primary causes of
reinforcement corrosion are (i) breakdown of the passive film on the steel by chloride ions and (ii) breakdown of
passivity by reduction of concrete pH, predominantly by reaction with atmospheric carbon dioxide. Increased use
of deicing salts and the increased concentration of carbon dioxide in modern environments from pollution, has
resulted in corrosion of the rebar becoming much more prevalent. Undamaged and chemically unaltered concrete
due to environmental issues is an excellent environment for steel reinforcement. But in situations that are highly
corrosive to reinforced concrete better options need to be explored.

Contributing Partners

Contact the Principal Investigator for information about partners.

Research Products

Bureau of Reclamation Review

The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.

Alternative Reinforcement for Concrete in Corrosive Environments (final, PDF, 1.2MB)
By Christine Daniels
Publication completed on September 30, 2016

High performance concrete (HPC), in combination with routine inspection and maintenance often succeeds in preventing or limiting rebar corrosion and related damage. Under certain environmental conditions however, corrosion can initiate, remain undetected and/or unrepaired, and cause damage to a structure. Several reinforcement alternatives such as stainless steel and zinc-coated steel have been in use for several decades. More recently, fiber reinforced polymer (FRP) composites (e.g., glass, carbon, and basalt) have been engineered and used in full-scale construction projects. This study shows that a determination of the viability of alternatives to plain steel rebar should not be based on reinforcement corrosion performance alone but should also include consideration of a structure's design, construction, operating environment, and expected lifetime plus the lifecycle costs associated with maintenance, repair, and replacement. In addition, the use of FRP rebar as concrete reinforcement should be further investigated.

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Last Updated: 6/22/20