Preparation and properties of fly ash-based geopolymer concrete with alkaline waste water obtained from foundry sand reg
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ORIGINAL ARTICLE
Preparation and properties of fly ash‑based geopolymer concrete with alkaline waste water obtained from foundry sand regeneration process S M Fuad Kabir Moni1 · O. Ikeora1 · C. Pritzel1 · B. Görtz1 · R. Trettin1 Received: 14 May 2019 / Accepted: 1 April 2020 © Springer Japan KK, part of Springer Nature 2020
Abstract The aim of the research was to investigate the influences of high alkaline content foundry sand regeneration wastes incorporated with fly ash in the production of geopolymer concrete. The fly ash-based geopolymer concrete was activated using alkaline solutions of sodium silicate and sodium hydroxide. The geopolymeric products were characterized using X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy and simultaneous thermal analysis. A higher compressive strength was observed in mechanical strengths test in the geopolymer and its respective foam concrete made of waste water in comparing to reference water (tap water). Furthermore, a packed arrangement and lower pore size distribution for both geopolymer and foam concrete were observed using nitrogen gas adsorption and mercury intrusion porosimetry, in contrast, to waste water and reference water. Keywords Geopolymers · Alkaline activator · Curing temperature · Foam geopolymer concrete · Waste water · Fly ash
Introduction High demand for environment-friendly construction materials has been the key challenge for the scientist in recent years [1]. The production of cement consumes energy and also emits greenhouse gases which have adverse impacts on the environment. Davidovits [2] reported that the production of about one ton of Portland cement results in the emission of one ton of carbon dioxide ( CO2) which varies with the technique used in the production process. The cement industry is the largest producer of CO2 in the world, due to a large amount of produced concrete (over 1 billion tons a year worldwide [1]). Partial replacement of cement using supplementary cementitious materials (SCMs) has been discovered with the aim of providing solutions towards reducing the dependency on cement. The effect was high compared to a 100% replacement of cement by a very low CO2 emission geopolymer [3]. McCaffrey [4] reported that generated CO2 emissions by the cement industries can be reduced by * S M Fuad Kabir Moni [email protected]‑siegen.de 1
Institute for Building and Materials Chemistry, University of Siegen, Paul Bonatz Str. 9–11, 57068 Siegen, Germany
limiting the amount of calcined material in cement. This can only be done by decreasing the amount of cement in concrete which will result in a decrease in the number of constructions dependent on cement compared to construction with others. A number of studies [5, 6] reported that the amount of CO2 emission generated from the production of geopolymers is about 60–80% less than the cement clinker. Geopolymers are in an inorganic polymeric structure formed by alkaline activation of raw materials containing silica and alumina [7]. The silica and
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