Novel Foaming-Agent Free Insulating Geopolymer Based on Industrial Fly Ash and Rice Husk

Abstract

This study highlights the synthesis of a new thermal insulating geopolymer based on the alkaline activation of fly ashes. A porous geopolymer material can be prepared without the addition of a foaming agent, using high ratio solution/ashes (activating solutions used are water, sodium or potassium hydroxide). In order to increase the porosity of the material and to make it more ecological, rice husks are incorporated into the formulation. The geopolymer materials were prepared at room temperature and dried at moderate temperature (105 °C) by a simple procedure. The microstructural characteristics of these new porous geopolymers were assessed by optical microscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and X-ray fluorescence (XRF). Infrared spectroscopy (FTIR) was used to confirm the geopolymerisation. The effect of the ratio solution/ashes and the percentage of the rice husk addition on thermal and mechanical analysis was evaluated. An insulating material for a solution/ashes ratio of 0.9 and a rice husk content of 15% having a λ value of 0.087 W/(m·K), a porosity of 61.4% and an Rc value of 0.1 MPa was successfully prepared.

Decarbonatization of Energy Sector by CO2 Sequestration in Waste Incineration Fly Ash and Its Utilization as Raw Material for Alkali Activation

“…There are, however, limited data considering the effect of various alkali activation treatments on the mechanical properties of solid products, which is reported to not exceed 10 MPa (compressive strength) [ 28 , 29 ]. For example, in the work of Beaino et al [ 30 ], the addition of waste biomass (rice husk) to high-calcium fly ash did not significantly improve the compressive strength of the material, which was reported to be <3 MPa. On the other hand, due to the high content of CaO, MSWI fly ashes can be considered promising materials for CO 2 sequestration via mineral carbonation.…”