EARLY HYDRATION OF A PORTLAND CEMENT IN WATER AND SODIUM HYDROXIDE SOLUTIONS: COMPOSITION OF SOLUTIONS AND NATURE OF SOLID PHASES

The effects of sodium hydroxide in the mixing water on the composition of the aqueous phase and the nature of the solid phases formed during the early hydration of an ordinary portland cement at a water/solids ratio of one were examined. At concentrations of 0.5 and 1 m, the nature and sequence of appearance of the new phases were the same as for water, but the time for depletion of sulfate from solution, primarily through the formation of ettringite, and the length of the dormant period in the hydration of the calcium silicate phases were shorter. At 2 and 4.5 m, the conversion of sulfate to sulfoaluminate was retarded and the higher alkali concentrations favoured the formation of a sodium-substituted monosulfate (dosch and zur strassen's u-phase) rather than ettringite. Also among the products at 4.5 m were a sodium sulphate (iii)-like phase, a soda-lime-silica hydrate with an estimated sodium oxide/silicon oxide molar ratio of 0.17 and a tetracalcium aluminate hydrate. Concentrations of silica in solution at the longest times of measurement were close to the boundary solubilities observed by kalousek (1944) in the system na2o-cao-sio2-h2o. Dissolved alumina concentrations were always very low and did not exceed 1 mm at the highest alkali hydroxide concentration.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00088846
• Corporate Authors:

  Pergamon Press, Incorporated

  Maxwell House, Fairview Park
  Elmsford, NY  United States  10523
• Authors:
  • WAY, S J
  • Shayan, A
• Publication Date: 1989-9

Language

• English

Media Info

• Pagination: p. 759-69
• Serial:
  • Cement and Concrete Research
  • Volume: 19
  • Issue Number: 5
  • Publisher: Elsevier
  • ISSN: 0008-8846
  • Serial URL: http://www.sciencedirect.com/science/journal/00088846

Subject/Index Terms

• TRT Terms: Cement; Chemical reactions; Concentration (Chemistry); Hydration; Hydroxides; Oxides; Silicon; Sodium
• ITRD Terms: 4758: Cement; 7132: Concentration (chem); 7195: Hydration; 7354: Hydroxide; 7372: Oxide; 7156: Reaction (chem); 7148: Silicon; 7197: Sodium
• Subject Areas: Materials;

Filing Info

• Accession Number: 00498107
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• Files: ITRD, TRIS
• Created Date: Sep 30 1990 12:00AM