Service Life Projection for Chloride-Exposed Concrete Reinforced with Black and Corrosion-Resistant Bars

Abstract

Corrosion-induced deterioration of reinforced concrete is a pervasive problem internationally. In response to this, an equation has been derived whereby the fraction of electrochemically independent reinforced concrete elements within which corrosion-caused damage has resulted after a given exposure time is calculated. The approach considers that all relevant variables conform to some distribution rather than being discrete, as is now known to be the case. These variables are (1) surface Clconcentration, (2) the effective Cldiffusion coefficient, (3) concrete cover, and (4) the critical Clconcentration threshold to initiate corrosion. Upon inputting (1) distribution parameters for the above variables, (2) the critical reinforcement corrosion loss to cause concrete damage, and (3) the average corrosion rate over the exposure period and numerically integrating, the fraction of elements that has experienced cracking/delamination after the selected time was determined. Upon repeating the calculation for incremental times, a cumulative distribution function plot for the occurrence of (1) corrosion initiation and (2) cracking/delamination was constructed. Example results are provided for concrete reinforced with both black bar and select corrosion-resistant reinforcements. The approach provides an improved tool for materials selection, service life projection, and maintenance planning.

3D simulation of localized steel corrosion in chloride contaminated reinforced concrete

“…According to many experimental studies, the critical chloride content to trigger steel corrosion in concrete is dependent on several factors including steel-concrete interface, binder type, steel potential, and PH of concrete pore solution, etc [21]. The threshold is generally recognized among researchers as a distributed parameter, which apparently arises because of the heterogeneous nature of concrete [22]. Here, to simplify our analysis, the critical chloride content in RC structures is chosen to be constant as 0.4% by weight of cement.…”

Concrete Corrosion Cracking and Transverse Bar Strain Behavior in a Reinforced Concrete Column under Simulated Marine Conditions

“…Rebar corrosion from chloride attack is a major cause of reduced performance in reinforced concrete (RC) structures [1,2]. When chloride ions from the sea permeate and spread through concrete cover and reach the embedded rebar, the protective oxide film (passive film) on the rebar surface is destroyed and corrosion begins.…”

Comparison of chloride penetration into surface-treated concrete in artificial and natural environments

“…Chloride-induced corrosion is a dominant cause of the deterioration of reinforced concrete structures (Hartt, 2012;Hobbs, 2001). Once the chloride content exceeds a threshold value, the passive film on the surface of the reinforcement will dissolve, and corrosion will occur in the presence of oxygen and moisture (Arya and Xu, 1995) and eventually cause the cracking and spalling of reinforced structures.…”