Reinforced Concrete is a common building material for construction of facilities and structures.
While concrete has high compressive strength, it has limited tensile strength. To overcome these tensile limitations, reinforcing bars are used in the tension side of concrete structures, and steel has historically been used as an effective and cost-efficient reinforcement material.
However, steel is susceptible to oxidation (rust), especially in coastal areas, locations where salt contaminated aggregates are used in the concrete mixture, and sites where aggressive chemicals and ground conditions exist. Where corrosion of steel reinforcement occurs, the resulting materials have a larger volume (2-5 times) than the metal product from which they were originally derived, leading eventually to cracking and spalling and further deterioration of the steel. The combination of ongoing deterioration and loss of reinforcement properties ultimately requires potentially significant and expensive outlays for repair and maintenance, and possibly the endangerment of the structure itself.
Repair or replacement costs associated with concrete degradation and spalling in Australia are estimated at $26 billion dollars.