The Effects of Corrosion on the Service Life of Reinforced Concrete Structures


Corrosion of reinforcing steel has been recognized as a leading cause of concrete degradation in civil infrastructure. The corrosion of steel reinforcing bars has been largely associated with chlorides. Seawater and deicing chemicals are two of the main sources of chlorides. Most of the bridges built in coastal areas are exposed to seawater.

Steel-reinforced bridges located in a snow-belt region start showing degradation signs in about 6 to 10 years after construction. Lack of maintenance and rehabilitation can turn these structurally deficient bridges into obsolete concrete structures well before their expected service life is reached. This blog post will analyze some of the corrosion effects on the durability of RC structures and how corrosion can be completely eliminated.

Corrosion-induced deterioration of reinforced concrete is generally controlled by three principal rate phenomena: corrosion rate, chloride diffusion rate, and deterioration rate. The chloride diffusion rate refers to the rate at which chloride ions diffuse through the concrete cover. Likewise, corrosion rate refers to the rate at which corrosion process progresses. The deterioration rate explains the pace at which concrete crack, spall, and delaminate. There are certain factors that influence these three rate phenomena.

Concrete degradation is a major concern for the construction industry as the cost to repair and replace deteriorated structures is in billions per year. Cement concrete has clearly become a material of choice for building small and large civil structures. A large number of studies and researches have been conducted to study the potential factors and conditions that can seriously damage the integrity of a structure and bring about or accelerate the deterioration process. Several measures have been developed and implemented to stop the chloride-induced corrosion of steel bars.

It becomes practically impossible for a degraded structure to reach its expected service life without rehabilitation. In North America, billions of dollars are spent annually in order to repair the structurally deficient concrete structures and make them last longer. Civil engineers are continuously looking for corrosion-free construction materials that can resist the environment effectively and provide the required strength. Civil engineers and researcher had failed to come up with a durable and cost-effective solution until they introduced composite materials as a potential corrosion solution.

Glass fiber reinforced polymer (GFRP) is a material of choice for concrete reinforcement in Canada and across North America because of its unique properties: corrosion resistance, high strength-to-weight-ratio, excellent fatigue performance, and electromagnetic immunity. A complete rust-free project can offer the service life of over 100 years without any major maintenance cost. This fact clearly demonstrates the significance of fiberglass reinforcing bars in building structures that have inbuilt corrosion resistance mechanism.

Composite fiberglass rebar ensures that the ability of a structure to resist environmental loading is greater than the environmental loading on the structure. Because of the effectiveness of composites in controlling corrosion, civil engineering applications of GFRP bars are increasing. TUF-BAR is one of the manufacturers of fiberglass rebar that provides structurally and economically feasible construction solutions in Canada and United States.