Preparation of Fly Ash-Ladle Furnace Slag Blended Geopolymer Foam via Pre-Foaming Method with Polyoxyethylene Alkyether Sulphate Incorporation

Abstract

This paper uses polyoxyethylene alkyether sulphate (PAS) to form foam via pre-foaming method, which is then incorporated into geopolymer based on fly ash and ladle furnace slag. In the literature, only PAS-geopolymer foams made with single precursor were studied. Therefore, the performance of fly ash-slag blended geopolymer with and without PAS foam was investigated at 29–1000 °C. Unfoamed geopolymer (G-0) was prepared by a combination of sodium alkali, fly ash and slag. The PAS foam-to-paste ratio was set at 1.0 and 2.0 to prepare geopolymer foam (G-1 and G-2). Foamed geopolymer showed decreased compressive strength (25.1–32.0 MPa for G-1 and 21.5–36.2 MPa for G-2) compared to G-0 (36.9–43.1 MPa) at 29–1000 °C. Nevertheless, when compared to unheated samples, heated G-0 lost compressive strength by 8.7% up to 1000 °C, while the foamed geopolymer gained compressive strength by 68.5% up to 1000 °C. The thermal stability of foamed geopolymer was greatly improved due to the increased porosity, lower thermal conductivity, and incompact microstructure, which helped to reduce pressure during moisture evaporation and resulted in lessened deterioration.

Ladle Furnace Slag: Synthesis, Properties, and Applications

“…The use of LF slag alone [60], activated LF slag, and the inclusion of additives like fly ash [129][130][131][132][133][134][135][136][137][138][139][140], fibers [141][142][143], and metakaolin [59,144] has been studied for forming geopolymers. The most critical factor in developing geopolymers is the hydration of binders, cement, slag, or fly ash to activate calcium aluminum silicate minerals using an alkali activator.…”

Fabrication and characterization of fly ash-based geopolymer and its performance for immobilization of heavy metal cations

“…One way to increase the fly ash utilization is to use as raw material for geopolymer synthesis, which can be applied as a building material to replace hydraulic cement-based materials (such as Portland cement or PC) or other useful materials. Since the main components of fly ash are alumina and silica, it is possible to use it as geopolymers' raw material [3,4]. Other materials such as kaolinite and metakaolin can be used as raw materials for geopolymers as well, but the manufacture of geopolymers from fly ash provides more advantages [5][6][7].…”