Among these methods, the use of protective coatings is one of the most effective and efficient methods because it can establish a physical and chemical barrier between the steel rebar and the corrosive environment. Many methods or techniques have been developed to protect steel rebar from corrosion in concrete structures, such as the addition of corrosion inhibitors or high-performance admixtures, use of protective coatings or corrosion resistant bars, and others. Therefore, steel reinforcement corrosion is one of the main causes of premature deterioration in reinforced concrete structures. In the meantime, corrosion reduces the steel-concrete bond strength and the cross-sectional area of steel rebar. When the stress reaches the tensile strength of concrete, cracking/spalling occurs in the concrete cover. The volume of corrosion products is usually two to six times greater than the volume of the original steel it consumes, resulting in tensile stress in the surrounding concrete. Once damaged, corrosion initiates in the presence of oxygen and moisture. However, this protective film can be destroyed by the ingress of chloride or carbonation of the concrete cover layer. Steel rebar in concrete structures is usually protected by a passive film formed due to the alkaline environment of fresh concrete.
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