Steel corrosion is a major problem with concrete structures. For concrete structures exposed to chlorides, once a critical chloride concentration is reached at the steel surface, corrosion starts to occur. For a given cover thickness, the corrosion initiation time depends…
Steel corrosion is a major problem with concrete structures. For concrete structures exposed to chlorides, once a critical chloride concentration is reached at the steel surface, corrosion starts to occur. For a given cover thickness, the corrosion initiation time depends on the chloride diffusivity. The diffusivity D for concrete is normally measured at the un-cracked state. However, o in reinforced concrete design, concrete members are allowed to crack in tension. Once cracking occurs, chloride can also diffuse through the crack at a faster rate governed by the crack diffusivity D . In the present study, finite element analysis is performed to study the effect of cracking on cr corrosion initiation in concrete with different values of Do. For various crack width and cover thickness, the time for critical chloride concentration to be reached at steel intersected by the crack is determined. Based on the simulation results, we derive the empirical equation for an equivalent diffusion coefficient (D ) which can be employed directly in the solution of the one-dimensional eq diffusion equation to calculate the corrosion initiation time. The study provides a convenient but accurate approach for predicting corrosion initiation under real world situations where cracks are present in a concrete structure.