Long-term corrosion protection of reinforcing bars via a self-responsive coating incorporating ZrP functional fillers

Abstract

The conventional coating of reinforcing bars exhibits inadequate anti-corrosion efficacy stemming from a non-specific, blind protection mechanism, poses a threat to the durability of concrete. We devised a novel self-responsive functional filler, L-arginine (LA) intercalated zirconium phosphate (LCZrP), synthesized via an intercalation reaction. This innovative filler was seamlessly integrated into an epoxy (EP) resin matrix, yielding a smart anticorrosive coating that harmoniously combines active and passive corrosion protection strategies. The integration of LCZrP within the coating matrix serves a trifecta of purposes: it extends the corrosion propagation path, effectively disperses nanofiller agglomeration, and enhances interfacial adhesion with the epoxy coating. Critically, the controlled release of corrosion inhibitors from the interlayer further fortifies the coating's resistance to corrosion, imparting a multi-layered protective shield. After enduring a 60-day immersion in a simulated concrete pore solution, the LCZrP/EP coating demonstrated exceptional durability, maintaining a low-frequency impedance modulus value consistently within the range of 4.27×1010 to 5.12×1010 Ω·cm2, marking a remarkable 34-fold enhancement over the performance of the epoxy coating alone. This breakthrough underscores the LCZrP/EP coating's potential as a groundbreaking solution for reinforcing bar protection in concrete, harnessing the complementary strengths of epoxy resin's physical barrier, the impermeability of two-dimensional lamellar structures, and the proactive release of corrosion inhibitors to forge a robust, multi-faceted passivation layer.