Preparation of sustainable of eco-friendly MWCNT-geopolymer composites with superior sulfate resistance
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ORIGINAL RESEARCH
Preparation of sustainable of eco-friendly MWCNT-geopolymer composites with superior sulfate resistance Hisham M. Khater 1
&
Abdeen M. El-Nagar 1
Received: 19 May 2020 / Revised: 16 July 2020 / Accepted: 31 July 2020 # Springer Nature Switzerland AG 2020
Abstract The main purpose of the paper is to prepare and characterize sustainable geopolymer composites with high potential to resist sulfate attack. The produced eco-friendly composites were produced from metakaolin as well blast furnace slag incorporating 10% of either silica fumes or glass waste powder as control mixes. multiwall carbon nanotube (MWCNT) was added from 0.01 up to 0.09% by weight. Addition of MWCNT results in an increased sulfate resistance up to 0.07% for both matrices incorporating glass waste or silica fume. This encourages the sustainability of the produced composites in marine environments. However, glass waste mixes exhibited greater stability and high mechanical properties than silica fume mixes as related to difference in their reactivity. Differential thermal gravimetric, FTIR, and XRD of hardened geopolymer composites with carbon nanotube of 0.01 up to 0.09 wt% depicted an increased amorphous geopolymer as well as hydrating phases with little evidence of ettringite formation up to 0.07%. Keywords Sustainable . Activation . Composites . Eco-friendly . MWCNT
1 Introduction Alkaline activation of aluminosilicate-rich materials for glassy constituent of industrial by-product converted into dense hardened material called either “geocement,” “geopolymer,” or “hydroceramic” identified by its excellent binding capabilities–excellent mechanical strength development and various other properties specifically attributed to traditional ceramics (smoothness/glassiness and luster) [1], which can be done at low temperatures (~ 25–80 °C) in a relatively short amount of time (~ 2–48 h) [2].The most common aluminosilicate source materials are blast furnace slag, fly ash with its both C and F types, glass waste, silica fume, metakaolinite materials, and any other natural or industrial waste materials that upon combination with adequate activator can mature materials for production of mortars and concretes [3, 4]. Geopolymer offered wide advantages of being eco-friendly with low carbon dioxide emission [5] as compared with traditional cement leading to be considered for a variety of * Hisham M. Khater [email protected] 1
Housing and Building National Research Centre (HBRC), 87 El-Tahreer St., Dokki, Giza, P.O. Box 11511, Cairo, Egypt
applications including fiber-reinforced composites [6], refractories [7], and as precursors to ceramic formation [8]. Geopolymers made from potassium activators are more refractory than sodium-based systems and can be withstand high temperature up to 1400 °C. Geopolymers of the composition K2O–Al2O3–4SiO2–11H2O have been shown to crystallize into leucite (K2O–Al2O3–4SiO2) upon heating [9]. As a way of reinforcing the formed geopolymer composites and increase their sustainability and resistivity against
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