Glass Ceramic Coated Rebar For High Corrosion Resistance And Enhanced Rebar/Concrete Bond

:the corrosion of rebars is one of the main reasons that can affect the service time of reinforced concrete. At some extreme circumstance such as heavy air pollution and seawater immersion, the rebars are heavily corroded. It is necessary to take some measures to reduce the rebars’corrosion.Four types of glass ceramic coatings were designed. Comparing the surface of coatings and the acid and alkali resistance of coatings, the optimum composition was chosen. The glass ceramic coatings were prepared by ball-milling raw materials. Single, mix, and duplex coatings were prepared by dip-coating on the rebar surface prior to sintering. The corrosion resistance and the bond strength at the rebar/concrete interface were investigated.The phase and morphology of coatings were studied by X-ray diffraction (XRD) and scanning electron microscope (SEM)analysis. The influence of coatings preparation on the tensile strength of rebars was investigated. The bond strength between the rebar and concrete was studied. The corrosion resistance was tested by electrochemical analysis such as potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS).It was found that the sintering process led to crystallization inside the coatings. SEM images demonstrated that the growth direction of dendrites was from the substrate onto thecoating and the coating was well bonded to the substrate. Compared with the bare rebar, all coated samplesshowed more than40%higher bond strength at the rebar/concrete interface.Immersed in synthetic seawater (3.5wt.%NaCl solution), single coated sample showed optimum anti-corrosion capability with higher bond strength at interface between the sample and concrete, the order of anti-corrosion ability was:single coated samples>double coated samples>mix coated samples.20figuers,21tables,79references.