LAUSR

Abstract Geopolymer foams (GFs), in which macro-porosity is introduced on purpose into the micro- and meso-porous geopolymer matrix, have received wide interests as for energy conservation. In this study, fly ash based geopolymer foams were prepared using sodium perborate as a foaming agent and washing liquid as a surfactant. Effects of the surfactant contents on mechanical and thermal properties of the prepared foams have been focused on our studies. With additions of surfactant from 0.1 to 0.5%, pores of the GFs became finer. All GFs prepared with and without the surfactant showed 28 day-curing compressive strength in the range of 4.21–4.82 MPa with improvement when the surfactant was added. Thermal conductivity of GFs fell in the range of 0.27–0.32 W/m.K. In addition, fire resistance test on 40 mm-thick GF panels showed satisfactory behavior. When temperature on the hot side was increased to 1000 °C and beyond, the temperature on the cold side remained only around 300 °C for up to 120 min. However, the GFs with 0.3 and 0.5% surfactant showed superior fire resistance to those without and with 0.1% surfactant. In general, residual compressive strength of all GFs after the high temperature exposure was slightly higher than the unexposed ones, with an exception for the ones being heated at 1000 °C possibly due to densification of the geopolymer networks.