Empirical model of corrosion rate for steel reinforced concrete structures in chloride-laden environments

Abstract

The corrosion rate of reinforcing steel is an important factor to determine the corrosion propagation of reinforced concrete structures in the chloride-laden environments. Since the corrosion rate of reinforcing steel is affected by several coupled parameters, the efficient prediction of which remains challenging. In this study, a total of 156 experimental data on corrosion rate from the literature were collected and compared. Seven empirical models for predicting the corrosion rate were reviewed and investigated using the collected experimental data. Based on the investigations, a new empirical model is proposed for predicting the corrosion rate in corrosion-affected reinforced concrete structures considering parameters including concrete resistivity, temperature, relative humidity, corrosion duration and concrete chloride content. The comparison between the experimental data and those predicted using the new empirical model demonstrates that the new model gives a good prediction of the corrosion rate. Furthermore, the uncertainty and probability characteristics of these empirical models are also investigated. It is found that the probability distributions of the model errors can be described as lognormal, normal, Weibull or Gumbel distributions. As a result, the new empirical model can provide an efficient prediction of the corrosion rate of reinforcing steel, and the model error analysis results can be utilized for reliability-based service life prediction of reinforced concrete structures under chloride-laden environments.

Modelling of Corrosion-Induced Concrete Cover Cracking Due to Chloride Attacking

“…In this work, the corrosion current density utilized is determined by Lu et al [29], and the expression is given as:…”

“…For reinforced concrete structures in naturally corrosive environments, combining Equations (29) to (30) and Equation (34), the following relationship is obtained:…”

“…However, in this model, two essential factors were ignored: the shape of the initial defects and the corrosion current density with time. These two factors are verified to play significant roles on the stresses induced by corrosion products residing in concrete, and subsequently affect the cover cracking time [23][24][25][26][27][28][29]. Therefore, in order to obtain a certain model with high accuracy with regard to the cover cracking problem, the coupling effects of the shape of initial defects and modified corrosion current density should be taken into account.…”

Influence of specimen dimensions and reinforcement corrosion on bond performance of steel bars in concrete

“…The chemical properties (high alkalinity) and physical performance (high resistivity) of the concrete cover in reinforced concrete (RC) structures are fundamental to ensure that the internal reinforcing steel bars in concrete are not affected by the external environment at short time (Shi et al, 2011). Passivation membrane on the surface of rebars is in a relatively steady state at a high alkalinity environment and destroyed when the alkalinity of concrete tends to decrease that causes the beginning of the corrosion of rebars in concrete (Lu et al, 2019). Val and Stewart (2003) pointed out that premature concrete deterioration caused by reinforcement corrosion is a major contributing factor to the loss of serviceability for existing RC structures.…”

A Simple Empirical Model for Predicting Weight Loss of Mild Steel due to Corrosion in NaCl Solution

“…As noted in the leterature, corrosion models are found mostly for atmospheric corrosion [17,18]. A study on empirical model for steel corrosion in concrete based on field data was done by Lu et al [19]. Corrosion model of steel in water containing Cl-ions has a great potential to be developed using an empirical approach based on the relationship between immersion time and variations in the concentration of NaCl in solution.…”