Experimental Study on Chloride Ion Diffusion in Concrete Affected by Exposure Conditions

Area of Science:

• Civil Engineering
• Materials Science
• Environmental Science

Background:

• Chloride ion ingress is a major cause of concrete degradation.
• Understanding chloride transport mechanisms is crucial for predicting concrete durability.

Purpose of the Study:

• To investigate the effect of different exposure conditions on chloride ion diffusion in concrete.
• To develop predictive models for chloride content based on experimental data.

Main Methods:

• Chloride ion diffusion experiments under three distinct exposure conditions: static immersion, circulating immersion, and dry-wet cycles.
• Application of Fick's second law to model chloride diffusion.
• Fitting experimental data to derive empirical equations for diffusion coefficients and surface chloride content.

Main Results:

• Chloride ion content increases with erosion age at a given depth.
• Chloride transport is faster in static sodium chloride solution compared to dry-wet cycles.
• Concrete under dry-wet cycles showed slightly higher chloride content than under continuous circulating immersion.

Conclusions:

• Exposure conditions significantly influence chloride ion diffusion in concrete.
• Developed empirical equations accurately predict chloride content and diffusion coefficients.
• The proposed method offers a reliable approach for analyzing and predicting chloride ion ingress in concrete structures.