# Chloride Ion Transport in Reinforced Concrete Structures Considering the Barrier Effect of Reinforcing Steel

## TL;DR

This paper studies how chloride ions move through reinforced concrete, considering how steel bars block their transport and how wetting-drying cycles affect durability.

## Contribution

The study introduces a mesoscale model that incorporates the blocking effect of reinforcing steel on chloride diffusion in concrete.

## Key findings

- Wetting–drying cycles significantly enhance chloride ingress in reinforced concrete.
- The rebar-induced blocking effect is non-negligible but less influential than compressive strength.
- Larger rebar diameters increase peak chloride concentration and accelerate chloride accumulation around aggregates.

## Abstract

A mesoscale model for chloride diffusion in reinforced concrete was established by considering the blocking effect of reinforcing steel. This model improved the accuracy of chloride concentration prediction and enhanced the reliability of durability-based service-life assessment. First, a series of chloride transport experiments under wetting–drying cycles was carried out on reinforced concrete specimens. These experiments were used to evaluate the effects of exposure condition, rebar blocking, and concrete compressive strength on chloride transport. Then, a mesoscale chloride diffusion model including the rebar-induced blocking effect was developed and validated. Finally, a sensitivity analysis of the key parameters was conducted. The results showed that, compared with concrete without longitudinal reinforcement, wetting–drying cycles had a stronger influence on reinforced concrete with longitudinal bars. The enhancing effect of wetting–drying cycles on chloride ingress was the strongest, followed by compressive strength and then the rebar-induced blocking effect, although the latter was still non-negligible. As the rebar diameter increased, the peak chloride concentration increased, and the chloride concentration around the aggregates also increased more rapidly.