Metakaolin-based geopolymer coatings on metals by airbrush spray deposition

Mao, Yangwu; Biasetto, Lisa; Colombo, Paolo

doi:10.1007/s11998-019-00310-6

Cited by 19 publications

(12 citation statements)

References 40 publications

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“…Alternatively, some quarry wastes are both rich in aluminosilicates and have the proper mineralogy, which allows their application as precursors to produce geopolymer cement and similar synthetic materials. Geopolymers are alternative binders which have diverse applications in various fields such as coatings and adhesives [14], fiber composite production [15], decorative stone artifacts [16], thermal insulations [17], building materials, low-energy ceramic tiles [18], waste encapsulation [9], thermal shock refractories [16], biotechnologies [19], etc. Geopolymers were first introduced by Joseph Davidovits in the early 1970s, where his primary aim was producing nonflammable and noncombustible plastics.…”

Section: Introductionmentioning

confidence: 99%

Quarry Waste as Precursors in Geopolymers for Civil Engineering Applications: A Decade in Review

Solouki

Viscomi²,

Lamperti³

et al. 2020

Materials

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Carbon footprint reduction of paving materials could be explored through recycling mining by-products into different applications, which will preserve natural resources and decrease environmental issues. One possible approach is to reuse quarry dust and mining ore waste as precursors in geopolymer applications. geopolymers are mineral polymers rich in aluminosilicates with an amorphous to a semi-crystalline three-dimensional structure. The current review aims to summarize the studies conducted during the past decade on geopolymers containing quarry dust and mine tailings. The first section discusses various precursors used for geopolymer cement production such as metakaolin, ground granulated blast furnace slag (GGBFS), fly ash, and quarry/mining ore wastes including silt, tungsten, vanadium, copper, gold, zinc, marble, iron, basalt, and lithium. Different calcination treatments and curing conditions have been summarized. In some cases, the precursors are required to be calcined to increase their reactivity. Both ambient temperature and elevated temperature curing conditions have been summarized. Less attention has been paid to room temperature curing, which is necessary for field and industrial implementations. Engineering properties such as compressive strength, density, durability and acid resistance, water absorption and abrasion of geopolymers containing mining waste were reviewed. One of the main barriers preventing the widespread use of waste powders, in addition to economic aspects, in geopolymers could be due to their unstable chemical structure. This was shown through extensive leachate of Na+ or K+ cations in geopolymer structures. The review of over 100 articles indicated the need for further research on different aspects of quarry waste geopolymer productions before its full industrial implementation.

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Section: Introductionmentioning

confidence: 99%

Quarry Waste as Precursors in Geopolymers for Civil Engineering Applications: A Decade in Review

Solouki

Viscomi²,

Lamperti³

et al. 2020

Materials

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“…The two mortars showed similar results. It is well-known that adhesion increases with the increase of roughness surface (Mao et al, 2020). However, in this case, different substrates were compared.…”

Section: Adhesive Strength and Impact Of Storage Conditionsmentioning

confidence: 99%

“…To evaluate this feature, several techniques were investigated. The effect of the curing temperature (40, 80, and 150 • C) of the geopolymer coating on aluminum plates was tested using the scratch test (Mao et al, 2020). The best result was reached at a temperature of 40 • C, without the formation of cracks or delamination.…”

Section: Introductionmentioning

confidence: 99%

Geopolymer Composite Coatings Based on Moroccan Clay and Sands for Restoration Application

et al. 2021

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This study aims to explore geopolymer binders and mortars based on local Moroccan clays and sands as coatings for the restoration of historical monuments in Morocco. For this, five substrates, one geopolymer binder, and two geopolymer mortars were investigated. The characterization of substrates reveals differences in terms of pH value, capillarity, contact angle, and surface roughness. These differences affect the coating thickness, which also depends on the viscosity, liquid to solid ratio, and granular skeleton of the geopolymer coating. High adhesive strength values (up to 9 MPa) were obtained on limestones. However, these values decreased with the increase of relative humidity. In the case of Fez stone, a stable adhesive strength value (3 MPa) was evidenced for all the coating formulations and at different storage conditions confirming the suitability of coating based on metakaolin, Moroccan clays, and sands for restoration applications.

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“…Mao et al studied sprayable GP films and found that curing at low humidity was beneficial compared to curing in closed conditions. 21 Their compositions were not entirely comparable to cast or AM geopolymer, though, because they required a much higher water content to be sprayable. As a consequence, setting was inhibited in closed conditions by the excess water while in low humidity the excess water could evaporate and the geopolymer nanoparticles were able to consolidate.…”

Section: Introductionmentioning

confidence: 99%

Depth dependence of hardness and reaction in metakaolin‐based geopolymers cured at low humidity

Samuel,

Kriven

2023

J Am Ceram Soc.

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Compared to metakaolin‐based sodium and potassium geopolymers cured at 20°C/100% relative humidity, geopolymers which were cured at 20°C/40% relative humidity were found to have considerable changes in the nanoscale structure and physical properties near the surface due to dehydration that occurred before completely hardening. For low‐humidity samples, the density in a thin near‐surface region was higher than the bulk, while porosity and BET specific surface area were greatly diminished. The microhardness at the exposed surface was low but increased sharply within a small depth before decreasing with depth to a constant value, which depended on the initial water content and charge‐balancing cation. 29Si NMR spectroscopy showed that the extent of reaction also varied with distance from the exposed surface. Both the elevated microhardness and incomplete reaction were detected at distances of up to 1.5 cm from the exposed surface, indicating that premature dehydration can cause microstructural changes over length scales that may be significant in large, ambiently cured 3D‐printed geopolymers. These effects are reduced by the use of sodium rather than potassium as the charge‐balancing cation and by raising the initial water content of the geopolymer, although higher water content caused greater surface deformation during drying.This article is protected by copyright. All rights reserved

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Metakaolin-based geopolymer coatings on metals by airbrush spray deposition

Cited by 19 publications

References 40 publications

Quarry Waste as Precursors in Geopolymers for Civil Engineering Applications: A Decade in Review

Quarry Waste as Precursors in Geopolymers for Civil Engineering Applications: A Decade in Review

Geopolymer Composite Coatings Based on Moroccan Clay and Sands for Restoration Application

Depth dependence of hardness and reaction in metakaolin‐based geopolymers cured at low humidity

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