Title: PROBABILISTIC TREATMENT OF CHLORIDE THRESHOLD

Author(s): Carmen Andrade, Fabiano Tavares, Nuria Rebolledo, David Izquierdo

Publication: Symposium Paper

Volume: 308

Issue:

Appears on pages(s): 1-14

Keywords: Chloride; Concrete; Corrosion; Statistics; Testing; Threshold.

DOI: 10.14359/51689179

Date: 6/1/2016

Abstract:
Chloride threshold is known to be a variable value depending on many parameters related to the cement chemistry, concrete characteristics and external environment. Several studies have been performed trying to find a general law that can predict the threshold in a particular concrete. Although this goal is the most rigorous approach to solving the problem, it seems very difficult to measure all influencing parameters in real work. Another approach consists in analysing the variability in a rational way. This is done in the present work following a recent method suggested in the new Model Code 2010, which considers deterministic to probabilistic models for service life prediction. The depassivation event is analysed first from its progressive nature which aims to determine chloride threshold variability, whose statistical distribution has been measured in the laboratory and which has shown to agree with observations in real structures. Also, comments are given on the meaning of the probability of depassivation and its consideration from a structural point of view. Finally an accelerated test method is mentioned which enables the determination of the chloride threshold in testing times shorter than 4 to 8 weeks. Testing of samples containing portland cement only and portland cement with slag are assessed with the accelerated test.