Title: Quantifying Relative Performance of Protection Systems for Use in Specifying Concrete for Chloride Exposures

Author(s): M. J. McCarthy and A. Giannakou

Publication: Symposium Paper

Volume: 212

Issue:

Appears on pages(s): 239-258

Keywords: chloride durability specification; controlled permeability formwork (CPF); corrosion inhibitor; silane coating; site exposed concrete; site produced concrete; stainless steel; waterproofer

DOI: 10.14359/12689

Date: 6/1/2003

Abstract:
Chloride exposures represent some of the most aggressive conditions in which concrete structures are located., Approaches followed in most national standards in the provision of durability for these normally give guidance in terms of mixture limits (minimum cement content and strength grade and maximum w/c), concrete cover depth and in some cases, cement type. In addition to controlling these, there are other routes that can extend performance, which concentrate either on (i) extending time to corrosion ini- tiation, by minimising rates of chloride ingress (eg controlled permeability formwork, silane coating and waterproofing admixtures) or (iij limiting corrosion rates, once conditions are such that the process can occur (eg corrosion inhibitors and stainless steel). This paper assesses the chloride resistance performance (in terms of chloride diffusion rates, chloride content at cover depth and reinforcement corrosion rates) of both conventional (methods in national standards) and other means of achieving corrosion resistant concretes and establishes how the more novel routes may fit within the mixture limit chloride durability specification frameworks. The results from tests on site produced concrete and concrete in a coastal exposure are used to explore the specification route for one of the novel systems (CPF).