Insights into material design, extrusion rheology, and properties of 3D-printable alkali-activated fly ash-based binders

Alghamdi, Hussam; Nair, Sooraj A.O.; Neithalath, Narayanan

doi:10.1016/j.matdes.2019.107634

Cited by 161 publications

(50 citation statements)

References 63 publications

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“…Similar improvements in tensile strength and elastic modulus were observed when the PLA/CNF composite was tested as material for 3D-printing, although strain at break and toughness values dropped [124]. Still, the shear forces in the 3D-printing process [129] resulted in orientation and stretching of these CNF bundles in the printing direction, leading to further increases in stiffness and storage modulus. In other words, beneficial controlled directional stiffening of the manufactured parts can be attained with the printing process [124].…”

Section: Nanocellulosesupporting

confidence: 57%

Vegetable Additives in Food Packaging Polymeric Materials

Munteanu

Vasile

2019

Polymers

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Plants are the most abundant bioresources, providing valuable materials that can be used as additives in polymeric materials, such as lignocellulosic fibers, nano-cellulose, or lignin, as well as plant extracts containing bioactive phenolic and flavonoid compounds used in the healthcare, pharmaceutical, cosmetic, and nutraceutical industries. The incorporation of additives into polymeric materials improves their properties to make them suitable for multiple applications. Efforts are made to incorporate into the raw polymers various natural biobased and biodegradable additives with a low environmental fingerprint, such as by-products, biomass, plant extracts, etc. In this review we will illustrate in the first part recent examples of lignocellulosic materials, lignin, and nano-cellulose as reinforcements or fillers in various polymer matrices and in the second part various applications of plant extracts as active ingredients in food packaging materials based on polysaccharide matrices (chitosan/starch/alginate).In this review various recent applications of plant-based additives (lignocellulosic fibers/nano-cellulose as well as bioactive plant extracts) as reinforcements and active ingredients in food packaging materials are illustrated. Natural polysaccharide biopolymers (such as chitosan/starch/alginate) are nontoxic, biodegradable, biocompatible, and largely used in food packaging: Chitosan is known for its broad antimicrobial activity and its excellent film-forming properties; alginates have good film-forming properties, retain moisture, reduce microbial counts, and retard oxidative off-flavors; and starch is also particularly important for its cheap price and its frequency in nature. For these reasons, this review will present applications of plant extracts as active ingredients in natural polysaccharide biopolymers: chitosan/starch/alginate. Classification of Natural Biodegradable Polymers and AdditivesNatural biodegradable polymers and additives are polymers formed naturally by the living organisms by enzyme-catalyzed reactions and reactions of chain growth from monomers which are formed inside the cells by complex metabolic processes [5].Natural additives can be high molecular weight (natural polymers), such as proteins (collagen, silk, and keratin), carbohydrates (starch and glycogen), lignin, cellulose, high molecular weight phenolics (tannins and derivatives), and low molecular weight active substances, such as cold-pressed oils, essential oils (organic volatile compounds, generally of low molecular weight,

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Section: Nanocellulosesupporting

confidence: 57%

Vegetable Additives in Food Packaging Polymeric Materials

Munteanu

Vasile

2019

Polymers

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“…A shortcoming with this approach is that such methods are empirical and does not provide any fundamental material parameter. However, a few researchers used yield stress of the concrete as a criterion [28,94,95] while Nerella et al [96] used the electric energy consumed by the concrete during pumping as a parameter to evaluate extrudability. Nevertheless, these methods are still single-point measurements.…”

Section: Materials Behaviour At Early Agementioning

confidence: 99%

“…However, one can use alternative binders instead of portland cement to improve sustainability. In this regard, several studies focused on developing 3D printable mixtures with alkali-activated binder systems [90,93,95,99,103,108,109,117,[150][151][152][196][197][198][199], calcium sulfoaluminate cements [128,142,200,201], limestone clay calcined cements [51,[202][203][204], and magnesium potassium phosphate cements [205,206]. However, there are challenges in designing printable concretes with binder systems such as limestone calcined clay due to chemical admixture compatibility issues [207,208].…”

Section: Sustainabilitymentioning

confidence: 99%

Extrusion-based concrete 3D printing from a material perspective: A state-of-the-art review

Mohan

Rahul

Schutter

et al. 2021

Cement and Concrete Composites

239

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“…The fly ash (85-95 wt.% of the total ash) consists of fine particles which are collected by electrostatic precipitation, or mechanical capture, from the flue gas, while the coarser bottom ash falls through the air stream to the bottom of the boiler and is removed mechanically [3]. The mineral composition of coal ash is represented mainly by the glass phase, similar only due to the simple filler effect [55,59,61], but to a certain extent, through participation in the dissolution processes and geopolymer gel formation [57,60,62,63]. Moreover, it was shown that calcite and limestone themselves alkali activated with waterglass, displayed cementitious properties [60,66].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Fly Ash-Based Geopolymers: Effect of Calcite Addition and Mechanical Activation

et al. 2020

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Blends of fly ash and natural calcite, mechanically activated for 0–400 s in a planetary mill, were used to synthesize geopolymers at ambient temperature. The calcite content in the blends was 0–10 wt.%. Sodium hydroxide solution was used as an alkaline agent. Mechanical activation of the raw material considerably enhanced its reactivity with respect to the alkaline agent, as was observed using Fourier-transform infrared spectroscopy, isothermal conduction calorimetry, thermogravimetry coupled with mass spectrometry analysis of the evolved gas, and SEM/EDS. The addition of calcite to the fly ash improved the compressive strength of the geopolymers, especially during the early age of curing. For 7 d aged geopolymers based on the 90% fly ash + 10% calcite blend, the strength was 8.0-, 3.5- and 2.9-fold higher than that for the geopolymers based on the unblended fly ash for 30 s, 180 s and 400 s mechanical activation time, respectively. Using Mössbauer spectroscopy, it was revealed that iron present in the fly ash did not play a significant part in the geopolymerization process. The dominant reaction product was sodium containing aluminosilicate hydrogel (N-A-S-H gel). Calcite was found to transform, to a small extent, to vaterite and Ca(OH)2 in the course of the geopolymerization.

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Insights into material design, extrusion rheology, and properties of 3D-printable alkali-activated fly ash-based binders

Cited by 161 publications

References 63 publications

Vegetable Additives in Food Packaging Polymeric Materials

Vegetable Additives in Food Packaging Polymeric Materials

Extrusion-based concrete 3D printing from a material perspective: A state-of-the-art review

Synthesis of Fly Ash-Based Geopolymers: Effect of Calcite Addition and Mechanical Activation

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