Fire-and-corrosion resistance dual-functional EGC coatings: Design and performance characterization

Abstract

Fire and corrosion are two fatal threats to steel structures, while the current fireproof and anti-corrosion measures for steel structures are implemented separately, resulting in multiple interfaces and complex protection systems. This study, therefore, is dedicated to developing an integrated fire-and-corrosion resistance coating for steel structures. A novel coating made from engineered geopolymer composites (EGC) with ultra-high ductility is designed to simultaneously provide fire and corrosion protection for steel structures. The feasibility of EGC as a coating agent was rigorously evaluated through analyses of its workability, mechanical properties, thermal performance, chloride resistance, and microscopic characteristics. The results indicated that EGC effectively met both short- and long-term operational requirements for coatings. EGC demonstrated significantly superior specific strengths (strength-to-mass ratio), lower thermal conductivity, and lower chloride diffusion coefficient than those of conventional cement-based coatings. It owns steel-like tensile ductility (exceeding 9 %) and excellent crack-width control ability, promising superior deformation compatibility under large deformation and desirable thermal/corrosion resistance. Additionally, the energy consumption and carbon emission of EGC decreased by 43 % and 82 %, respectively, compared to traditional cement-based coatings. Capitalizing on the inherent fire resistance of geopolymer, alone with its high ductility, superior crack-control ability, exceptional thermal insulation and chloride resistance abilities, EGC emerges as a highly promising material for fire and corrosion protection applications, offering a sustainable and efficient solution for protective coatings in steel structures.