Fire testing of geopolymer based syntactic foams

This investigation deals with core materials (syntactic foams) made by embedding randomly dispersed spheres in a Geopolymer matrix. This type of syntactic foam was employed as a light core material for composite sandwich panels with high strength face skins. Syntactic foams are a special kind of particulate composite materials made of a matrix and a gas-filled aggregate consisting of spherical microspheres. However, the filler is randomly dispersed in the matrix, in a way to obtain a homogeneous and isotropic macroscopic behavior. A Geopolymer matrix was the binder in both materials. For the first type of cores ceramic spheres were used, having a density of 0.4-0.48 gr/cm ³. In the second type, the spheres were expanded polystyrene beads with a density of 0.025 gr/cm³. Core materials made of ceramic and polystyrene spheres were subjected to the "Ohio State University (OSU) heat release" test. The fire testing results of the two core materials types are presented.