Implications of Uncertainty in Service Life Modeling: Example of Chloride-Induced Corrosion of Reinforcement in RC Structure

Service life estimates in the context of forensic engineering provide information valuable to quantify the observed (or alleged) damage. However, service life estimates are often a single, deterministic value despite recognition of the variance in the parameters used for the estimation. This paper evaluates the sources of variance in service life estimates and their consequence on the final life estimate through an example of initiation period of chloride induced corrosion of reinforcement in reinforced concrete structures. The effect of industry standard variances, including variance allowed within ASTM test procedures, and ACI tolerances, on the uncertainty in the corrosion initiation period were explored. The analysis helped identify the parameters that play a dominant role in the variance of the initiation period estimate. The paper highlights the value of this probabilistic information to the involved parties in properly estimating the scale and impact of the observed (or alleged) damage.