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Adsorption and hydration behavior of tricalcium aluminate- water and tricalcium aluminate-gypsum-water systems in the presence of superplasticizers

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  1. National Research Council of Canada
FormatText, Article
SubjectAdmixtures; plasticizers; adsorption; hydration; gypsum; aluminate cement; calcium aluminate hydrates; calorimeters; conductivity; C3a; ettringite; melamine resins; naphthalene compounds; sulfonation
Abstract
Additions of 1, 2, and 4 percent sulfonated melamine or naphthalene formaldehyde retard the hydration of C[3]A and the rate of conversion of hexagonal to cubic aluminate hydrate. This effect is more pronounced at high dosages of the superplasticizer. Rate of adsorption of the superplasticizer is higher in the C[3]A-H[2]O system than in the hexagonal or cubic phase; adsorption is irreversible. In a non-aqueous medium only the hexagonal phase adsorbs small amounts of superplasticizer. Reaction between tricalcium aluminate and gypsum to form ettringite is accelerated in the presence of superplasticizer. The exothermal reaction occurring in this system as a result of the reaction of excess tricalcium aluminate is delayed in the presence of the superplasticizer. Adsorption experiments on the tricalcium aluminate-gypsum mixture prehydrated for different periods show that the rate of adsorption is generally in the decreasing order 0, 1 hr, 2 days, 15 min, 30 min, and 5 min. In the non-aqueous medium only small amounts of superplasticizer are adsorbed. Adsorption was irreversible in all cases.
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  • Journal of the American Concrete Institute 80, no. 3 (May 1983): 235–241.
LanguageEnglish
Peer reviewedYes
IdentifierDBR-P-1115
NRC numberNRCC 22476
NRC-IRC-3036
NPARC number20375978
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Record identifierd659e50d-2505-420e-9842-c8b2157f7d01
Record created2012-07-23
Record modified2024-03-22
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