The structure directing effect of cations in aqueous silicate solutions. A 29Si-NMR study

Abstract

The structure directing effect of cations in aqueous silicate solutions -a Si-29-NMR study Wijnen Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publicationCitation for published version (APA): Wijnen, P. W. J. G., Beelen, T. P. M., Haan, de, J. W., Ven, van de, L. J. M., & Santen, van, R. A. (1990). The structure directing effect of cations in aqueous silicate solutions -a Si-29-NMR study. Colloids and Surfaces, 45,[255][256][257][258][259][260][261][262][263][264][265][266][267][268]

Alkali–silica reaction: Kinetics of chemistry of pore solution and calcium hydroxide content in cementitious system

“…Several researchers [10,37,38] found that Na + ions increased the dissolution rate of silica (which consequently increases the rate of ASR reaction). In contrast, other researchers [8,39] reported that the system containing K + ions appears to be reacting faster than the one containing Na + ions. In the current study, it is interesting to note that, as shown in Fig.…”

“…In addition, the contents of Ca(OH) 2 and the expansions of mortar bars were also quantified to investigate the relationship between Cement and Concrete Research 71 (2015) [36][37][38][39][40][41][42][43][44][45] these parameters and the change in the chemistry of pore solution obtained from samples undergoing ASR. Specifically, the effects of following parameters on the chemistry of pore solution and the content of calcium hydroxide (Ca(OH) 2 ) are described: (a) length of curing time (up to 130 days), (b) temperature (23°C, 38°C, and 55°C), and (c) presence of reactive or non-reactive aggregates.…”

Biosilicification: the role of the organic matrix in structure control

“…The molecular mechanism for the condensation reaction is believed to involve a bimolecular collision between an ionised and an un-ionised silicic acid molecule as shown [5,57,62,66]. Silicic acid molecules oligomerise in such a way to produce a maximum number of siloxane (Si-O-Si) bonds and a minimum of uncondensed Si(OH) groups [5], and so the oligomers cyclise during the early stages of the process to give rings containing predominantly 3±6 silicon atoms linked by siloxane bonds.…”

Influence of alkyl chain length on the stability of n-alkyl-modified reversed phases. 2. Model dissolution study

“…The tetrahydroxysiloxane Qo level in the methanol-water solution seemed to be rather low compared with results of silica dissolution studies published (5, 11). Possibly, the subsequent oligomerization reaction proceeded relatively fast compared with the monomer dissolution under our experimental conditions.…”

“…Furthermore, the proportions of the oligomeric silicates in particular were affected by the type of solvent used for dissolution studies as is the case with silica substrates (5, 11).…”