Bond Deterioration of Reinforcing Steel in Concrete Due to Corrosion

Abstract

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Reliability-Based Prediction of Chloride Ingress and Reinforcement Corrosion of Aging Concrete Bridge Decks

“…It follows a gamma distribution with parameters 2 and 0.783, mean value of 2.57 kg/m 3 (0.71% by cement weight), standard deviation of 1.36 kg/m 3 (0.38% by cement weight) and a coefficient of variation of 0.53. The simulation results are very close to the field measurements (Amleh 2000;Lounis and Mirza 2001), which yielded a mean value of 0.73% by cement weight and a coefficient of variation of 0.72.…”

“…However, if C th is assumed lognormal with a mean of 1.44 kg/m 3 and a coefficient of variation of 10%, this probability reduces to 80%. From the different field observations and measurements made on the bridge (Amleh 2000;Lounis and Mirza 2001), including delamination, half-cell potential, chloride content, and resistivity, this probability is about 85%, which suggests that a more reliable estimate of the mean threshold content for this deck is about 1.35 kg/m 3 . If the time to corrosion initiation (T i ) can be approximated by a lognormal distribution with mean µ Ti and coefficient of variation V Ti , it is possible to derive the following analytical relationship for predicting of the probability of corrosion P f (t): …”

“…The bridge deck had a specified design thickness of 150 mm, 25 mm concrete cover for the top reinforcement mat, and 28 MPa concrete strength. Prior to demolition, a detailed condition assessment of the bridge was undertaken (Amleh 2000;Lounis and Mirza 2001). A summary of the relevant data to this paper is presented in the following section.…”

An integrated system for bridge management using probabilistic and mechanistic deterioration models: Application to bridge decks

“…The deck was severely deteriorated because of the inadequate quality control in construction and the aggressive environment resulting from the frequent use of de-icing salts in winter. A detailed condition assessment was carried out in 1999 (i.e., after 40 years) on the bridge deck prior to its demolition (Amleh, 2000;Fazio, 1999). This assessment resulted in hundreds of data points that indicated a considerable variation in the parameters affecting the chloride contamination of the deck and corrosion of the top mat of reinforcing steel throughout the deck.…”

“…By definition a deterioration model is a link between a measure of infrastructure condition that assesses the extent and severity of damages, and a vector of explanatory variables that represent the factors affecting infrastructure deterioration such as age, material properties, applied loads, environmental conditions, etc. (Ben-Akiva and Gopinath, 1995). The inherit random nature of these variables, existence of other variables that are not typically observed or measured, and use of simplified physical models and statistical assumptions lead to a wide variation in the condition of bridge components.…”