Title:
Chloride Profiles in Carbonated Concrete
Author(s):
Yoshiki Tanaka
Publication:
Materials Journal
Volume:
119
Issue:
1
Appears on pages(s):
3-13
Keywords:
carbonation; diffusion in composite; efflux; fitting; partially carbonated zone; porosity; saturation; seasonal variation; tortuosity
DOI:
10.14359/51733144
Date:
1/1/2022
Abstract:
In a deeply carbonated concrete deck under field exposure at the coast, chloride profiles in a carbonated layer were complex, and its diffusivity seemed to be markedly different from that in a noncarbonated layer. This paper discusses what the profiles mean. First, the study attempted to determine both apparent diffusion coefficients of chloride ions in the noncarbonated and carbonated layers by fitting. Then, the fast ion transfer in the carbonated layer was recognized. In addition, it was found that the complex chloride
profiles cannot be well expressed by the theoretical or numerical solutions for a composite medium consisting of the layers as far as the surface chloride content is assumed to be constant. Subsequently, the influence of a seasonal variation in the surface chloride content upon the profile was examined. The results show that the complex chloride profiles should happen due to the high diffusivity in the carbonated layer under the variable surface chloride content, suggesting that the chloride ions run out from the carbonated surface easier.