Influence of the dry/wet ratio on the chloride convection zone of concrete in a marine environment

A convection zone appears in chloride content analysis in the concrete surface layer of when it is subjected to long-term to the marine atmosphere and tidal zones. To reveal the influence of the corrosion environment and concrete materials on the peak chloride concentration Cmax and convection zone depth dx, this paper studies the evolution of the convection zone of concrete in long-term field experiments in a marine tidal zone and indoor experiments based on simulated drying-wetting cycles. Concrete includes Portland cement concrete and highperformance concrete containing ground granulated blast furnace slag (GGBS) and fly ash. Results indicate that greater the dry/wet ratio is, the earlier the onset of the convection zone is. Both the Cmax and dx increase with the dry/wet ratio. The Cmax and dx follows a power function with exposure time. Additionally, concrete containing GGBS and fly ash can significantly decrease Cmax, but cannot retard convection zone development in marine tidal environment compared with Portland cement concrete.

Automated summary

This study investigates the convection zone of concrete in marine tidal environments, revealing that the dry/wet ratio has a significant impact on the onset and development of the convection zone. Additionally, concrete containing GGBS and fly ash can lower the peak chloride concentration but does not retard the convection zone development compared to Portland cement concrete.