Title: Modeling Chloride Diffusion in Concrete with Linear Increase of Surface Chloride

Author(s): Shengjun Zhou

Publication: Materials Journal

Volume: 111

Issue: 5

Appears on pages(s): 483-490

Keywords: chloride diffusion; modeling; surface chloride concentration

DOI: 10.14359/51686989

Date: 9/1/2014

Abstract:
Mathematical models are derived to predict chloride diffusion in concrete with an initial exposure period having a linear increase of surface chloride and decreasing diffusivity, and subsequent periods with a decreasing or constant diffusivity. A new method was developed to integrate the modeling results over these periods. Modeling examples indicated that chloride diffusion is slower in the short term with a slower linear buildup of surface chloride and in the long term with a longer period of decreasing diffusivity. In the aforementioned conditions, modeling by assuming a constant surface chloride predicts a faster diffusion with the average diffusivity and a slower diffusion with the minimum diffusivity. Modeling by assuming a constant surface chloride with a decreasing diffusivity for the entire exposure duration predicts faster diffusion within a period (75 years) and slightly slower diffusion after that.