Innovative and Sustainable Uses of Volcanic Ash as a Natural Pozzolan for Dust Abatement and Unpaved Roadway Improvement

Sleep, Matthew D.; Masley, Morgan

doi:10.1061/9780784482148.023

Cited by 2 publications

(1 citation statement)

References 8 publications

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“…Natural pozzolanic materials, such as VAs, can be used as supplementary cementitious materials. They require relatively few pre-treatments (i.e., grinding, calcination or chemical activation) before they can be used as alkali-activated materials (AAM) [ 13 ]. Although many natural resources undergo the clinkerization process at 1350–1450 °C to produce OPC, AAM materials are obtained at relatively low temperatures of 25–100 °C or 600–700 °C if the calcination process is required.…”

Section: Introductionmentioning

confidence: 99%

Volcanic Ash as a Sustainable Binder Material: An Extensive Review

2021

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The construction industry is affected by the constant growth in the populations of urban areas. The demand for cement production has an increasing environmental impact, and there are urgent demands for alternative sustainable solutions. Volcanic ash (VA) is an abundant low-cost material that, because of its chemical composition and amorphous atomic structure, has been considered as a suitable material to replace Portland cement clinker for use as a binder in cement production. In the last decade, there has been interest in using alkali-activated VA material as an alternative material to replace ordinary Portland cement. In this way, a valuable product may be derived from a currently under-utilized material. Additionally, alkali-activated VA-based materials may be suitable for building applications because of their good densification behaviour, mechanical properties and low porosity. This article describes the most relevant findings from researchers around the world on the role of the chemical composition and mineral contents of VA on reactivity during the alkali-activation reaction; the effect of synthesis factors, which include the concentration of the alkaline activator, the solution-to-binder ratio and the curing conditions, on the properties of alkali-activated VA-based materials; and the mechanical performance and durability properties of these materials.

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Section: Introductionmentioning

confidence: 99%

Volcanic Ash as a Sustainable Binder Material: An Extensive Review

2021

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Dissolution of Volcanic Ash in Alkaline Environment for Cold Consolidation of Inorganic Binders

Dal Poggetto,

Douwe,

Stroscio

et al. 2024

Materials

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A systematic study on the dissolution in concentrated alkali of two volcanic ashes from Cameroon, denoted as DAR and VN, is presented here. One volcanic ash, DAR, was 2 wt% richer in Fe and Ca and 4 wt% lower in Si than the other, designated as VN. Such natural raw materials are complex mixtures of aluminosilicate minerals (kaersutite, plagioclase, magnetite, diopside, thenardite, forsterite, hematite, and goethite) with a good proportion of amorphous phase (52 and 74 wt% for DAR and VN, respectively), which is more reactive than the crystalline phase in alkaline environments. Dissolution in NaOH + sodium silicate solution is the first step in the geopolymerisation process, which, after hardening at room temperature, results in solid and resistant building blocks. According to XRD, the VN finer ash powders showed a higher reactivity of Al-bearing soluble amorphous phases, releasing Al cations in NaOH, as indicated by IPC-MS. In general, dissolution in a strong alkaline environment did not seem to be affected by the NaOH concentration, provided that it was kept higher than 8 M, or by the powder size, remaining below 75 µm, while it was affected by time. However, in the time range studied, 1–120 min, the maximum element release was reached at about 100 min, when an equilibrium was reached. The hardened alkali activated materials show a good reticulation, as indicated by the low weight loss in water (10 wt%) when a hardening temperature of 25 °C was assumed. The same advantage was found for of the room-temperature consolidated specimens’ mechanical performance in terms of resistance to compression (4–6 MPa). The study of the alkaline dissolution of volcanic ash is, therefore, an interesting way of predicting and optimising the reactivity of the phases of which it is composed, especially the amorphous ones.

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Innovative and Sustainable Uses of Volcanic Ash as a Natural Pozzolan for Dust Abatement and Unpaved Roadway Improvement

Cited by 2 publications

References 8 publications

Volcanic Ash as a Sustainable Binder Material: An Extensive Review

Volcanic Ash as a Sustainable Binder Material: An Extensive Review

Dissolution of Volcanic Ash in Alkaline Environment for Cold Consolidation of Inorganic Binders

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