Preliminary Investigation of Geopolymer Foams as Coating Materials

Abstract

Various types of coatings are applied to the surface of an object or substrate to improve surface properties or extend service life, which in turn is associated with cost reductions. The main objective of this study was to develop a technique for the additive application of foamed geopolymers to existing structures and vertical surfaces. The base material was a fly ash-based geopolymer modified with sand. Hydrogen peroxide and aluminum powder were used as foaming agents. In this study, the feasibility of using an air gun with variable nozzles to apply the layers of foamed geopolymers was assessed, and the effects of nozzle diameter and the spray gun’s operating pressure were analyzed. The next stage of the study was a visual assessment of the layering of the foamed material. The foamed geopolymer layering tests verified the occurrence of the foaming process, and the applied geopolymer surface showed a reasonably good adhesive bond with the vertical wall. In addition, in this paper, we present the laser particle size results of the base materials and their oxide composition. In addition, thermal conductivity tests for the foamed geopolymer materials, compressive strength tests, and microstructure analysis via scanning electron microscopy were carried out.