Improvement in the geopolymer-to-steel bond using a reactive vitreous enamel coating

摘要

This study examines the effectiveness of a reactive vitreous enamel coating on the surface of reinforcing steel on bond strengths and microstructural interactions with a geopolymer-based binder. Steel rods with and without the glassy enamel coating rich in Al, Si, and Ca were tested for bond strength when embedded in a Class F fly ash geopolymer. Microstructural characterization using scanning electron microscopy and energy-dispersive X-ray spectroscopy was also used to investigate the spatial distribution in micro-structure and chemistry at the interface. The use of a reactive enamel coating on reinforcement was found to increase bond strengths by approximately 2.5 times based on push-out test specimens. The presence of the reactive enamel coating was found to decrease porosity at the interface and also provide a more gradual transition in microstructure and chemistry between the steel reinforcement and the geo-polymeric matrix. Results of the study support investigation of the developed coating system for reinforcing bars, fibers, and stay-in-place formwork systems.