Preparation and characterization of a hybrid alkaline binder based on a fly ash with no commercial value

Mejía, Johanna M.; Rodríguez, Erich D.; Gutiérrez, Ruby Mejía de; Gallego, Nidia C.

doi:10.1016/j.jclepro.2015.05.044

Cited by 52 publications

(23 citation statements)

References 27 publications

(2 reference statements)

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“…Fernandez‐Jiménez and Palomo suggested that a suitable coal FA must have loss on ignition values lower than 5% . However, there exist studies related to the production of alkali‐activated materials using different industrial wastes or by‐products derived from thermal processes with higher contents of organic matter, including coal fly ash, coal bottom ash, municipal solid waste ashes, palm oil fuel ash, and sugar cane bagasse ash . Considering that the high content of un‐reacted material reduces the effectiveness and reactivity of these wastes as precursors, blending with another more‐reactive aluminosilicate may be required.…”

Section: Summary and General Considerationsmentioning

confidence: 62%

Management and valorisation of wastes through use in producing alkali‐activated cement materials

Bernal

Rodríguez

Kirchheim

et al. 2016

J of Chemical Tech & Biotech

134

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ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. Abstract 15There is a growing global interest in maximising the re-use and recycling of waste, to 16 minimise the environmental impacts associated with waste treatment and disposal. Use 17 of high-volume wastes in the production of blended or novel cements (including alkali-18 activated cements) is well known as a key pathway by which these wastes can be re-19 used. This paper presents a critical overview of the urban, agricultural, mining and 20 industrial wastes that have been identified as potential precursors for the production of 21 alkali-activated cement materials, or that can be effectively stabilised/solidified via 22 alkali activation, to assure their safe disposal. The central aim of this review is to 23 elucidate the potential advantages and pitfalls associated with the application of alkali-24 activation technology to a wide variety of wastes that have been claimed to be suitable 25 for the production of construction materials. A brief overview of the generation and 26 characteristics of each waste is reported, accompanied by identification of opportunities 27 for the use of alkali-activation technology for their valorisation and/or management. 28

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Section: Summary and General Considerationsmentioning

confidence: 62%

Management and valorisation of wastes through use in producing alkali‐activated cement materials

Bernal

Rodríguez

Kirchheim

et al. 2016

J of Chemical Tech & Biotech

134

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“…However, not only pH but also the presence of soluble silica influences hardening of fly ash-rich binder Influence of selected activating methods on hydration processes... [112,113]. Mejía et al [111] proved that using NaOH and sodium silicate as activators of hybrid cement containing 70% of fly ash may be beneficial in case of fly ash showing high loss of ignition and exhibiting no commercial value.…”

Section: High Alkaline Activationmentioning

confidence: 99%

“…One of the advantages of hybrid cements over geopolymers is that mixtures containing cement do not require elevated temperature for hardening and forming solid structure [102,111,114]. Moreover, activation methods during which pH of solution is raised gradually in situ can be used.…”

Section: Moderate Alkali Activationmentioning

confidence: 99%

Influence of selected activating methods on hydration processes of mixtures containing high and very high amount of fly ash

Wilińska

Pacewska

2018

J Therm Anal Calorim

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Binders containing fly ash as cement substitute have been used for many years. Typical amount of fly ash in cement composite does not exceed 35% of mass of binder. Replacement of substantial amount of cement mass by fly ash results in retardation of hydration of binder and deterioration of some concrete properties, e.g. delay in setting time and reduction in early compressive strength. These inconveniences may be reduced using proper method of activation. In this paper, possibilities to activate binding mixtures containing high and very high amount of fly ash and low amount of Portland cement were discussed basing on the literature reports as well as on our own research results. Several activating methods were described, such as mechanical activation, exchanging of part of components of binder (cement, fly ash or both of them) by more reactive fine-grained material, chemical activation by the use of alkaline activators as well as combined methods. Possibilities of using these methods were discussed in relation to amount of fly ash introduced as replacement of cement and kind of fly ash used. Usefulness of calorimetry and thermal analysis methods was also presented.

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“…A wide variety of such industrial wastes is described in the literature with very variable composition [ 3 , 4 ] thus making their alkali-activation a complex issue. Apart from coal fly ash, blast furnace slag, calcined kaolins, and few others for which it can be said confidently that are suitable for EN 197 cements and can also be properly and successfully employed in the production of geopolymers or hybrid alkaline cements, few recent works have been aimed at valorization of poorly reactive/not-recycled waste materials [ 5 , 6 ]. In the present study two different steel slags were used with metakaolin and sand to generate an aluminosilicatic matrix via alkali activation.…”

Section: Introductionmentioning

confidence: 99%

Design of Inorganic Polymer Mortar from Ferricalsialic and Calsialic Slags for Indoor Humidity Control

Kamseu

Lancellotti

Modolo³

et al. 2016

Materials

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Amorphous silica and alumina of metakaolin are used to adjust the bulk composition of black (BSS) and white (WSS) steel slag to prepare alkali-activated (AAS) mortars consolidated at room temperature. The mix-design also includes also the addition of semi-crystalline matrix of river sand to the metakaolin/steel powders. The results showed that high strength of the steel slag/metakaolin mortars can be achieved with the geopolymerization process which was particularly affected by the metallic iron present into the steel slag. The corrosion of the Fe particles was found to be responsible for porosity in the range between 0.1 and 10 µm. This class of porosity dominated (~31 vol %) the pore network of B compared to W samples (~16 vol %). However, W series remained with the higher cumulative pore volume (0.18 mL/g) compared to B series, with 0.12 mL/g. The maximum flexural strength was 6.89 and 8.51 MPa for the W and B series, respectively. The fracture surface ESEM observations of AAS showed large grains covered with the matrix assuming the good adhesion bonds between the gel-like geopolymer structure mixed with alkali activated steel slag and the residual unreacted portion. The correlation between the metallic iron/Fe oxides content, the pore network development, the strength and microstructure suggested the steel slag's significant action into the strengthening mechanism of consolidated products. These products also showed an interesting adsorption/desorption behavior that suggested their use as coating material to maintain the stability of the indoor relative humidity.

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Preparation and characterization of a hybrid alkaline binder based on a fly ash with no commercial value

Cited by 52 publications

References 27 publications

Management and valorisation of wastes through use in producing alkali‐activated cement materials

Management and valorisation of wastes through use in producing alkali‐activated cement materials

Influence of selected activating methods on hydration processes of mixtures containing high and very high amount of fly ash

Design of Inorganic Polymer Mortar from Ferricalsialic and Calsialic Slags for Indoor Humidity Control

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