Glass ceramic coated rebar for high corrosion resistance and enhanced rebar-concrete bond

Low-softening glass ceramic coatings were applied onto the surface of reinforcing steel rebars via slurry dip-coating and sintering. This work investigated the tensile strength properties of coated rebars, the phase compositions and microstructures of these coatings and their corrosion resistance and bond strength at the rebar-concrete interface. X-ray diffraction analysis revealed that the sintering process led to crystallisation inside the coatings. Scanning electron microscopy images demonstrated that the growth direction of dendrites was from the substrate onto the coating and the coating was well bonded to the substrate. Samples of mix-coated and duplex-coated rebars showed a much lower corrosion rate than a single-coated sample. Compared with the bare rebar, all the coated samples showed more than 40% higher bond strength at the rebar-concrete interface.