Properties of some blended high-alumina cements

Majumdar, A.J.; Singh, B.

doi:10.1016/0008-8846(92)90040-3

Cited by 71 publications

(43 citation statements)

References 4 publications

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“…[10][11][12] It seems that the reverse has happened in this case where the aluminate ions produced from the corrosion of aluminium have interacted with a silicate based cement system and facilitated the formation of strä tlingite.…”

Section: Corrosion Of Aluminiummentioning

confidence: 87%

Corrosion of aluminium and magnesium in BFS composite cements

Setiadi

Milestone

Hill³

et al. 2006

Advances in Applied Ceramics

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Legacy radioactive wastes arising from reprocessing of nuclear fuels in the UK are classified as intermediate level waste (ILW), which contain things such as aluminium and magnesium. Blast furnace slag (BFS) composite cements are used to encapsulate ILW. These cements have a high pH which is advantageous to limit the mobility of some of the radioactive species but can cause corrosion of metals. The present paper describes some fundamental aspects of corrosion of aluminium and magnesium in BFS composite cements.The corrosion of aluminium produced an interface between aluminium and cement which was porous with a series of zones containing bayerite (Al(OH) 3 ) and strä tlingite (2CaO.Al 2 O 3 .SiO 2 .8H 2 O). With magnesium, the main corrosion product was found to be brucite (Mg(OH) 2 ) and the porous zone was less pronounced. The hydration of the bulk cement did not appear to be affected by the corrosion of these metals.

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Section: Corrosion Of Aluminiummentioning

confidence: 87%

Corrosion of aluminium and magnesium in BFS composite cements

Setiadi

Milestone

Hill³

et al. 2006

Advances in Applied Ceramics

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“…Chemical modification of CAC has been conducted using highly alkaline solutions, including sodium hydroxide and sodium silicates [14] favouring the direct precipitation of C 3 AH 6 or Si-substituted katoite as main reaction products respectively, hence avoiding the porosity development associated with the conversion of the intermediate metastable phases. Inclusion of supplementary siliceous cementitious materials (silica fume [15,16], fly ash [15,17], blast furnace slag [18]) has also been demonstrated to be an effective pathway to limit deleterious conversion, through promoting the formation of secondary products such as strätlingite (C 2 ASH 8 ) and calcium silicate hydrate (C-S-H).…”

Section: Preprint Version Of Accepted Article Please Cite As: Ma Cmentioning

confidence: 99%

Identification of the hydrate gel phases present in phosphate-modified calcium aluminate binders

Chavda

Bernal

Apperley

et al. 2015

Cement and Concrete Research

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The conversion of hexagonal calcium aluminate hydrates to cubic phases in hydrated calcium aluminate cements (CAC) can involve undesirable porosity changes and loss of strength.Modification of CAC by phosphate addition avoids conversion, by altering the nature of the reaction products, yielding a stable amorphous gel instead of the usual crystalline hydrate products. Here, details of the environments of aluminium and phosphorus in this gel were elucidated using solid-state NMR and complementary techniques. Aluminium is identified in both octahedral and tetrahedral coordination states, and phosphorus is present in hydrous environments with varying, but mostly low, degrees of crosslinking. A 31 P/ 27 Al rotational echo adiabatic passage double resonance (REAPDOR) experiment showed the existence of aluminium-phosphorus interactions, confirming the formation of a hydrated calcium aluminophosphate gel as a key component of the binding phase. This resolves previous disagreements in the literature regarding the nature of the disordered products forming in this system.

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“…Although the microsilica favors the gehlenite formation, 15 some authors 10 pointed out that it does not prevent the hydrogarnet (C 3 AH 6 ) formation. However, Majumdar and Singh et al 10 . and Fu et al 14 .…”

Section: Introductionmentioning

confidence: 99%

Microstructural Evolution of Calcium Aluminate Cements Hydration with Silica Fume and Fly Ash Additions by Scanning Electron Microscopy, and Mid and Near‐Infrared Spectroscopy

López¹,

Calvo²,

Olmo³

et al. 2008

Journal of the American Ceramic Society

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Calcium aluminate cement (CAC) is less commonly used as ordinary Portland cements (OPCs) for structural concrete, is relatively expensive, but may have certain advantages when used for solidification of wastes; it introduces rapid strength gain and has a higher resistance to chemical attack than OPC. However, the most widely identified degradation process suffered by CAC is the so‐called conversion of hexagonal calcium aluminate hydrate to a cubic form. Mixes of CAC with silica fume (SF) or fly ash (FA) represent an interesting alternative for the stabilization of CAC hydrates, which might be attributed to a microstructure based mainly on aluminosilicates. This paper deals with the microstructure of cement pastes fabricated with binders of CAC–SF and CAC–FA, and their evolution over time. Mid infrared and near infrared spectroscopy have been used to assess the microstructure of these formulations. Microstructural characterization was completed by backscattering electron microscopy observation and microanalysis.

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Properties of some blended high-alumina cements

Cited by 71 publications

References 4 publications

Corrosion of aluminium and magnesium in BFS composite cements

Corrosion of aluminium and magnesium in BFS composite cements

Identification of the hydrate gel phases present in phosphate-modified calcium aluminate binders

Microstructural Evolution of Calcium Aluminate Cements Hydration with Silica Fume and Fly Ash Additions by Scanning Electron Microscopy, and Mid and Near‐Infrared Spectroscopy

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