Service life variation in RC columns exposed to chloride attack: a time-dependent deterministic and probabilistic examination

Abstract

Service life prediction for reinforced concrete (RC) is usually performed through deterministic or probabilistic methods in regard to anticipating the phenomenon of chloride attack. The field investigation results from long-term exposure can provide reasonable data for evaluating service life, but corrosion can progress differently due to local conditions, even with the same mix proportions and exposure conditions. This paper uses two methods (deterministic and probabilistic) to explore the variation of the service life of RC columns which have been exposed to chloride attack for 3.5–4.5 years. Fieldwork was carried out on four RC columns exposed to tidal and atmospheric zones, and various chloride profiles from 25 cores were obtained. The chloride diffusion coefficients and surface chloride contents were analysed in relation to the heights at which the cores were taken and the corresponding exposure conditions. Increasing surface chloride content and decreasing diffusion coefficient with time are considered both for the deterministic and probabilistic method, and the results of the two methods are compared. The limitations of the field investigation results from the RC columns exposed to atmospheric conditions are explored in detail.

Keywords:

• Durability; concretecorrosion;chloride attack
• deterministic method, probabilistic method
• field investigation
• time-dependent diffusion