Effect of Hydrophobic Surface Treatment in Lowering Ionic Transport into Concrete

The present study concerns hydrophobic surface treatments with silane-based liquid and creme on the concrete surface against external ionic transport for the application to concrete pavement coating. To quantify their effectiveness in mitigating the ionic penetration, water absorption and chloride transport were measured. Especially, back-scattered image analysis and the electrochemical impedance spectroscopy were used to identify the effect of pore-blocking at the interface of coating agents and the concrete. As a result, the surface treatment with both liquid and creme could significantly reduce the water absorption and chloride ingresses at all depths of measured concrete, due to a modification of the porosity. Moreover, the surface treatment on concrete substrate increased the polarization resistance, thereby enhancing the resistance to ionic transport into the concrete, and the creme type was slightly more effective at the same dosage of treatment.