Full-time domain rust expansion investigation and visual evaluation of reinforced concrete under synergistic protection

Abstract

Reinforced concrete undergoes corrosion-induced expansion in chloride environments. To enhance the chloride resistance of reinforced concrete and analyze the corrosion behavior before and after protection, The steel bar was treated with a γ-aminopropyltriethoxysilane (KH550) solution using molecular self-assembly and incorporated a cementitious capillary crystalline waterproofing material during concrete mixing. Electrochemical tests accelerated chloride erosion, while digital image correlation (DIC) technology continuously monitored strain and displacement fields on the specimen’s surface. X-ray CT provided a three-dimensional visualization and analysis of corrosion products. Scanning electron microscopy and X-ray energy spectroscopy revealed the microstructural degradation and failure mechanisms of the concrete under various protective measures. The study indicates that chloride-induced rebar corrosion generates expansive stresses that drive the integration, coherence, and propagation of cracks in the concrete protective layer. Both silane coupling agent molecular coatings and cementitious capillary crystalline waterproofing material effectively inhibit chloride-induced rebar corrosion and delay the development of corrosion-induced cracks. Combined use of self-assembly technology and cementitious capillary crystalline waterproofing material offers superior resistance to chloride erosion compared to single protective measures.