Analysis of the variability of chloride threshold values in the literature

Efforts are being devoted in standards and construction codes in order to give rules and guidelines for designing durable structures. Also efforts are focused in developing the models in a more accurate approach to the calculation of the service life of concrete structures. Service life models consider that reinforced concrete exposed to chloride polluted environments initiate corrosion when a certain amount of chlorides arrives to the rebar surface. The so-called chloride threshold level is considered as an essential parameter for assessing the probability of reinforcement corrosion, and becomes one of the key parameters needed for service life prediction, being of interest to have testing methods and expressions to introduce in the models. Numerous studies have been carried out to establish a critical chloride level for the onset of corrosion, but a wide range of chloride threshold values has been suggested which makes not feasible to define a single value. Present paper includes the analysis of the variability of the chloride threshold values published in the literature. Data from mortar and concrete and from laboratory and field exposure are compiled and included in the analysis. The influence of the testing method used for determination and several variables are considered.