Study of some synthetically prepared hydrous alkali calcium silicates

Way, Steve; Shayan, A

doi:10.1016/0008-8846(92)90115-c

Cited by 9 publications

(4 citation statements)

References 13 publications

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“…The OH − concentrations are generally greater and less dependent on chemical composition at higher bulk Ca content. These results are consistent with existing solubility measurements in the CaO- [21][22][23][24]35,55,56 which show the same trends in dissolved Si, Ca and OH − concentrations with respect to the bulk alkali content and Ca/Si ratio. Here, dissolved Al concentrations were generally found to be lower at higher Ca/Si* ratios, and higher in samples more highly concentrated in alkalis.…”

Section: Aqueous Phase Analysissupporting

confidence: 92%

“…19 The essentially aluminium-free C-(N,K-)S-H formed during plain Portland cement hydration can incorporate a significant content of alkalis (up to 20% of the amount of Na or K added 21 ), which decreases as a direct function of the Ca/Si ratio. 21 A good understanding of C-(N,K-)S-H solubility currently exists up to bulk Na concentrations of 0.8 M NaOH, 8,9,[21][22][23][24] which represents the pH range relevant to most cement-based materials ( pH ≤ 13.5), but fewer solubility data for this phase are available for K-containing materials in the corresponding composition range. 21,22,25,26 These data are essential in understanding the long-term stability of C-(N,K-)-S-H and in the development of thermodynamic models for this phase, enabling simulation of the chemistry of cementbased materials in service.…”

Section: Introductionmentioning

confidence: 99%

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Composition–solubility–structure relationships in calcium (alkali) aluminosilicate hydrate (C-(N,K-)A-S-H)

et al. 2015

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The interplay between the solubility, structure and chemical composition of calcium (alkali) aluminosilicate hydrate (C-(N,K-)A-S-H) equilibrated at 50 °C is investigated in this paper. The tobermorite-like C-(N,K-)A-S-H products are more crystalline in the presence of alkalis, and generally have larger basal spacings at lower Ca/Si ratios. Both Na and K are incorporated into the interlayer space of the C-(N,K-)A-S-H phases, with more alkali uptake observed at higher alkali and lower Ca content. No relationship between Al and alkali uptake is identified at the Al concentrations investigated (Al/Si ≤ 0.1). More stable C-(N,K-)A-S-H is formed at higher alkali content, but this factor is only significant in some samples with Ca/Si ratios ≤1. Shorter chain lengths are formed at higher alkali and Ca content, and cross-linking between (alumino)silicate chains in the tobermorite-like structure is greatly promoted by increasing alkali and Al concentrations. The calculated solubility products do not depend greatly on the mean chain length in C-(N,K-)A-S-H at a constant Ca/(Al + Si) ratio, or the Al/Si ratio in C-(N,K-)A-S-H. These results are important for understanding the chemical stability of C-(N,K-)A-S-H, which is a key phase formed in the majority of cements and concretes used worldwide.

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Section: Aqueous Phase Analysissupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Composition–solubility–structure relationships in calcium (alkali) aluminosilicate hydrate (C-(N,K-)A-S-H)

et al. 2015

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“…The composition of the simulated C-(N-565 )S-H gel also captures the relatively higher Na content measured in this phase at lower Ca/Si ratios 566 [77]. The comparisons between the simulated and reported solubility data in the other alkali 567 concentration ranges studied are also good (Appendix D), with the exception of some of the data 568 reported at NaOH concentrations > 1 M in [80].…”

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confidence: 63%

A thermodynamic model for C-(N-)A-S-H gel: CNASH_ss. Derivation and validation

Myers

Bernal

Provis

2014

Cement and Concrete Research

212

118

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“…In the case of fine crushed stone, the water-binder ratio is relatively high, and the compressive strength of aerated concrete is low, leading to possible collapses of the mortars in the mold. In contrast, the mortars made with coarse crushed stone are susceptible to segregation and as a consequence, the realization of air-entrapping is relatively difficult [4]. In this study the fineness of the crushed stones was fixed in the range of 10~15 % (by weight) residue on 80 µm sieve.…”

Section: Influence Of the Fineness Of Crushed Stonesmentioning

confidence: 99%

Use of Clayish Crushed Stone for Production of Aerated Concrete

Chen

Xu³

2006

KEM

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Aerated concrete is a new type of building materials. Clayish crushed stones are regarded as solid waste disposals in China. This paper reports the research outcomes of an experimental study on using clayish crushed stone for the production of aerated concretes of B05 and B06 grade. Hydro-thermal synthesis reaction, mixing proportions, gas-forming and their influences on the concrete performance are investigated. Proper mixing proportions and some important technical parameters are proposed for material design. The microstructure of aerated concrete made with clayish crush stone is analyzed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicate that the hydration products of clayish aerated concrete are composed of poor crystallized C-S-H (B), blade- and needle-shaped Tobermorite and a small amount of granular Hydrogarnet. A homogeneous and densified microstructure was obtained in the aerated concretes with negligible amount of clay after the hydro-thermal reaction in the mixture.

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Study of some synthetically prepared hydrous alkali calcium silicates

Cited by 9 publications

References 13 publications

Composition–solubility–structure relationships in calcium (alkali) aluminosilicate hydrate (C-(N,K-)A-S-H)

Composition–solubility–structure relationships in calcium (alkali) aluminosilicate hydrate (C-(N,K-)A-S-H)

A thermodynamic model for C-(N-)A-S-H gel: CNASH_ss. Derivation and validation

Use of Clayish Crushed Stone for Production of Aerated Concrete

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