Title: Quality and Cover Thickness of Concrete Based on the Estimation of Chloride Penetration in Marine Environments

Author(s): K. Takewaka and S. Mastumoto

Publication: Symposium Paper

Volume: 109

Issue:

Appears on pages(s): 381-400

Keywords: adsorption; chlorides; concrete durability; corrosion; cover; diffusion; marine atmospheres; reinforced concrete; thickness; Materials Research

DOI: 10.14359/2124

Date: 8/1/1988

Abstract:
For selecting concrete cover for reinforcement in marine structures, consideration of the corrosion protection of steel bars is indispensable. Therefore, requirements for quality and thickness of concrete cover must be established so the concrete cover prevents chlorides, oxygen, water, etc., from reaching reinforcement through the life of the structure. To insure good performance of concrete cover, the chloride penetration process should be understood. A dualistic diffusion equation was adopted to explain this. In solving equations, the following were clarified through referral to data of experiments: 1) The relationship between the quality of concrete and chloride diffusion coefficients; 2) the effect of the chemical or physical adsorption of chloride in concrete on the diffusion process; and 3) boundary condition to concrete surface for chloride concentration in various marine environments. On the basis of these studies, a close agreement between observed and calculated values was obtained. Through the calculations of chloride penetration, the rational design for quality and thickness of concrete in various marine environments has been suggested.