This technology is an electrochemical concrete surface treatment method that inhibits the leaching of alkali ions. It involves installing a titanium mesh plate as an anode on the surface of reinforced concrete, using the internal rebar as a cathode, and applying an electric current to form a calcium hydroxide film between the concrete surface and the plate.
Concrete is highly alkaline (pH ~12.5) due to calcium hydroxide produced during hydration, causing alkali ions like hydroxide to leach when in contact with water. Conventional methods, such as surface painting or membrane coating, suffer from reduced bond strength when submerged for long periods and increased leaching at localized cracks caused by wave action, which negatively impacts the ecosystem. Natural carbonation is difficult to control as its rate and depth vary with indoor/outdoor conditions and sunlight. Electrochemical treatments for rebar corrosion have limitations, as they cause hydrogen gas generation and hydroxide ion dissociation around the rebar.
This technology uses an electrolyte chamber member that covers the concrete surface over the anode, filled with a lithium borate electrolyte solution to enhance electrical mobility between the anode and cathode, with the edges sealed to prevent leakage. The control phase manages current, voltage, and duration, supplying 250–1000mA and 5–20V for four weeks. Concrete structures treated with this method are also included in the scope of the patent. Applicable to river/coastal revetments, underwater structures, water intake/purification facilities, fishways, and waterfront concrete, it modifies the concrete surface layer itself rather than relying on a coating that can peel off, thereby reducing alkali leaching into the aquatic ecosystem.
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