Carbonation and Corrosion Problems in Reinforced Concrete Structures

Abstract

Reinforced concrete (RC) has been commonly used as a construction material for decades due to its high compressive strength and moderate tensile strength. However, these two properties of RC are frequently hampered by degradation. The main degradation processes in RC structures are carbonation and the corrosion of rebars. The scientific community is divided regarding the process by which carbonation causes structural damage. Some researchers suggest that carbonation weakens a structure and makes it prone to rebar corrosion, while others suggest that carbonation does not damage structures enough to cause rebar corrosion. This paper is a review of the research work carried out by different researchers on the carbonation and corrosion of RC structures. The process of carbonation and the factors that contribute to this process will be discussed, alongside recommendations for improving structures to decrease the carbonation process. The corrosion of rebars, damage to passive layers, volume expansion due to steel oxidation, and crack growth will also be discussed. Available protection methods for reducing carbonation, such as rebar structure coating, cathodic protection, and modifier implementation, will also be reviewed. The paper concludes by describing the most significant types of damage caused by carbonation, testing protocols, and mitigation against corrosion damage.

Photoactive Cements: A Review

“…In general, mortars with a higher sand content (1:2) showed reduced resistance to carbonation and water absorption, which was consistent with the previous research by Huang et al [ 157 ], which showed that CO 2 gas penetrates the concrete surface through the sand-cement gap [ 157 ]. This means that increasing the volume of sand in concrete also increases CO 2 penetration [ 158 ]. Duan et al [ 156 ] noted an improvement in carbonation resistance by 77%, 62%, and 42% for fluidized bed fly ash geopolymer paste samples containing 1%, 3%, and 5% NT, respectively, after 180 days of exposure.…”

Analysis of the Effect of Protective Properties of Concretes with Similar Composition on the Corrosion Rate of Reinforcing Steel Induced by Chloride Ions

“…In this expression, j 1 (a) is the value of the mass flow of chloride ions passing through the plane situated at "a" distance x = a; ρ 1 1 , ρ 1 2 , and ρ 1 n are the averaged mass densities of ion Cl − at the midpoints of consecutive intervals (0, g), (g, 2g), . .…”

“…Depending on their location and function, building structures are exposed to many harmful factors. The most common causes of reinforcement corrosion and concrete damage are carbonation and chloride penetration [ 1 ]. The faster the carbon dioxide or chlorides penetrate the concrete, the faster the passive layer on the rebar is destroyed and the corrosion process begins [ 2 ].…”

Polymers As Concrete Healing Materials

“…The number and size of the cracks increase the permeability of concrete, which is one of the critical parameters reducing its durability [12]. Chloride ions, carbon dioxide and oxygen dissolved in water lead to corrosion on the rebar, resulting in potential structural failures [13][14][15]. Therefore, many traditional maintenance and fixing methods have been implemented to avoid this type of degradation.…”