Chloride Diffusion in Concrete Protected with a Silane-Based Corrosion Inhibitor

Area of Science:

• Materials Science
• Civil Engineering
• Corrosion Science

Background:

• Reinforced concrete structures face durability issues due to chloride ingress from marine environments and de-icing salts.
• Chloride diffusion into the cement matrix is a critical factor influencing concrete structure longevity and corrosion risk.

Purpose of the Study:

• To evaluate the effectiveness of a silane-based surface-applied corrosion inhibitor (CI) in mitigating chloride penetration in concrete.
• To quantify the reduction in chloride diffusion and assess the inhibitor's performance across different concrete compositions.

Main Methods:

• Accelerated chloride diffusion tests were conducted on concrete specimens treated with the silane-based CI.
• Natural chloride diffusion tests were performed to measure the apparent diffusion coefficient (D_app).
• Concrete bulk electrical resistivity was measured to confirm the inhibitor's mechanism of action.

Main Results:

• The corrosion inhibitor significantly reduced chloride penetration compared to untreated specimens.
• Reductions in the chloride diffusion coefficient (D_nssn) ranged from 30-60% in accelerated tests.
• Natural diffusion tests showed a decrease in apparent diffusion coefficient (D_app) of approximately 75% in treated concrete.

Conclusions:

• The silane-based CI effectively reduces chloride ingress in concrete, irrespective of water/cement ratio, cement type, or dosage.
• The primary mechanism of action is a water-repellent effect, confirmed by increased concrete bulk electrical resistivity.
• The study confirms the CI's potential to enhance the durability of concrete structures exposed to chloride-rich environments.