Introduction
Chloride ingress is a leading cause of reinforcement corrosion in concrete structures exposed to aggressive environments, including marine and coastal conditions (ACI 222R) and de-icing salts. This study evaluates the long-term chloride resistance of Xypex-treated concrete panels installed in 1995 at the Lascelles Wharf, Port of Geelong, Australia. These panels have been subjected to a highly aggressive marine environment—positioned in the splash zone—and exposed to bulk chemicals and fertilizers from port off-loading operations. Chloride penetration analyses conducted in 2014 (CHEM-142) and 2021 (CHEM-155) provide a comparative assessment of Xypex crystalline technology’s effectiveness in preventing chloride-induced deterioration.
Experimental Procedure
The chloride penetration assessment was conducted using the following approach:
- Core Sampling: Chloride profiles were generated from core samples extracted from Xypex-treated concrete slabs.
- Acid-Soluble Chloride Analysis: Chloride content was measured at various depth intervals to assess ingress patterns.
- Diffusion Coefficient Calculation: The effective diffusion coefficient was determined from the chloride concentration gradients.
- Threshold Benchmarking: Chloride concentrations at reinforcement depth were compared to the 0.4% threshold to assess the risk of corrosion initiation.
Results and Discussion: 2014 vs. 2021
The chloride diffusion profiles indicate that chloride concentrations at reinforcement depth remained well below the corrosion threshold in both 2014 and 2021. The calculated diffusion coefficient showed remarkable decrease, signifying that Xypex-treated concrete improves its suppression of chloride ingress over time, with no evident degradation in protection performance.
Conclusion
The 2014 vs. 2021 chloride ingress comparison demonstrates that Xypex-treated concrete improves its long-term resistance to chloride penetration, significantly reducing the risk of reinforcement corrosion over time. The decrease of the diffusion coefficient over time suggests that Xypex crystalline technology provides a permanent and self-sustaining protective effect, distinguishing it from conventional treatments, barriers and coatings that degrade with age.