Fly ash based geopolymer thin coatings on metal substrates and its thermal evaluation

Abstract

Class F fly ash based Na-geopolymer formulations have been applied as fire resistant coatings on steel.The main variables for the coating formulations were Si: Al molar and water: cement weight ratios. Wehave determined that the adhesive strength of the coatings strongly depend on geopolymer composition.The ease with which geopolymer can be applied onto metal surfaces and the resultant thickness depend on the water content of the formulation. Adhesive strengths of greater than 3.5MPa have been achieved on mild steel surfaces for compositions with Si:Al of 3.5. Microstructure evolution and thermal properties of the optimised coating formulations show that they have very promising fire resistant characteristics.