Thermally Aerated Geopolymers as Lightweight Construction Material

Abstract

In this research work, thermal foaming of bottom ash and sodium silicate geopolymer is proposed as a production process for light weight bricks. The composition and temperatures were studied and optimized to get the most suitable intumescence properties for the lightweight construction applications. For this purpose, four different compositions (i.e., 10%, 20%, 30%, and 40% bottom ash (BA)) were cured at four different curing temperatures (CT) (i.e., 200, 400, 500, and 600 °C). Sodium silicate (SS) to sodium hydroxide (SH) ratio was kept constant in order to keep the activation capacity of the solution constant in all the samples so that the effect of composition and CT could be studied effectively. All samples were characterized by bulk density, foamability, compression test, XRD, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), water absorption index (WAI), and weight loss index (WLI). These characterizations finally led to the optimized parameters to get the most appropriate intumescence properties. It was found that bottom ash and sodium silicate geopolymer foams have good potential to produce lightweight aerated blocks.