Title:
Carbonation-Chloride Interactions and Their Influence Corrosion Rates of Steel in Concrete
Author(s):
Harold Roper and Daksh Baweja
Publication:
Symposium Paper
Volume:
126
Issue:
Appears on pages(s):
295-316
Keywords:
carbonation; cements; chlorides; corrosion; Materials Research
DOI:
10.14359/2177
Date:
8/1/1991
Abstract:
Corrosion of steel reinforcement within concrete structural elements is a major problem in both research and practice. Laboratory studies have been conducted on fundamental mechanisms of corrosion within concrete in the presence of high chloride and others under conditions of reduced alkalinity. However, little has been published on the interactive effects of these two conditions and the ways in which corrosion rates of steel in concrete are thereby influenced. These two conditions occur concurrently under many practical environmental exposures. This paper presents data on methodology used to determine corrosion rates of steel in concrete. Information on corrosion activities in both carbonated and high-chloride environments is presented with reference to mechanisms involved in breakdown of steel passivation. Interactive effects of the two conditions are examined for a range of concrete types and grades. The data suggest that for normal reinforced concrete structural elements, the interactive effects of carbonation and chloride ion ingress lead to much more rapid corrosion than where the two phenomena occur independently. The interactive effects of carbonation and chloride ions as they influence concretes under service conditions are discussed. In particular, the reduction of carbonation rate in the presence of high-chloride ion concentrations is noted.