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Effect of chemical admixtures on the expansion of shrinkage-compensating cement containing a pre-hydrated high alumina cement-based expansive additive
The effect of chemical admixtures on ettringite formation and expansion of expansive cement containing a pre-hydrated high alumina cement-based additive (H-HAC) is discussed. Nine chemical admixtures including surfactants, accelerators, retarders and a bonding agent were investigated. SNF - type superplasticizer can be used to reduce ultimate expansion in cement containing H-HAC expansive additive by accelerating early ettringite formation and expansion. SMF - type superplasticizer can also be used to reduce expansion in expansive cement containing H-HAC expansive additive by accelerating early ettringite formation and expansion at very early hydration times. Early suppression of expansion through chemical interaction may possibly result in a higher ultimate expansion by addition of an optimum amount of superplasticizer. Sodium lignosulfonate and sodium citrate can be used to control expansion through suppression of ettringite formation at very early hydration ages. Optimization of dosage is required. Sucrose significantly reduces expansion because it restricts the formation of ettringite so effectively that even a vey low concentration will result in minimal expansion. Inorganic salts, e.g. CaCl2, NaCl and Na2SO4, can be used to promote expansion of cement containing H-HAC - based expansive additive. The role of chemical interaction of these salts on the expansion process is not clear. A possible expansion mechanism would attribute increased ultimate expansion to the slight delay of ettringite formation in fresh and weak cement paste. SBR latex - based bonding agents can increase the expansion of cement containing H-HAC - based expansive additive possibly through chemical interaction effects at early ages. Optimization of dosage is required.
Effect of chemical admixtures on the expansion of shrinkage-compensating cement containing a pre-hydrated high alumina cement-based expansive additive
The effect of chemical admixtures on ettringite formation and expansion of expansive cement containing a pre-hydrated high alumina cement-based additive (H-HAC) is discussed. Nine chemical admixtures including surfactants, accelerators, retarders and a bonding agent were investigated. SNF - type superplasticizer can be used to reduce ultimate expansion in cement containing H-HAC expansive additive by accelerating early ettringite formation and expansion. SMF - type superplasticizer can also be used to reduce expansion in expansive cement containing H-HAC expansive additive by accelerating early ettringite formation and expansion at very early hydration times. Early suppression of expansion through chemical interaction may possibly result in a higher ultimate expansion by addition of an optimum amount of superplasticizer. Sodium lignosulfonate and sodium citrate can be used to control expansion through suppression of ettringite formation at very early hydration ages. Optimization of dosage is required. Sucrose significantly reduces expansion because it restricts the formation of ettringite so effectively that even a vey low concentration will result in minimal expansion. Inorganic salts, e.g. CaCl2, NaCl and Na2SO4, can be used to promote expansion of cement containing H-HAC - based expansive additive. The role of chemical interaction of these salts on the expansion process is not clear. A possible expansion mechanism would attribute increased ultimate expansion to the slight delay of ettringite formation in fresh and weak cement paste. SBR latex - based bonding agents can increase the expansion of cement containing H-HAC - based expansive additive possibly through chemical interaction effects at early ages. Optimization of dosage is required.
Effect of chemical admixtures on the expansion of shrinkage-compensating cement containing a pre-hydrated high alumina cement-based expansive additive
Einfluß von chemischen Zusätzen auf die Ausdehnung von schwindungskompensiertem Zement mit einem auf vorhydratisiertem Ausdehnungszusatz auf der Basis von Hochtonerdezement
Fu, Y. (author) / Gu, P. (author) / Xie, P. (author) / Beaudoin, J.J. (author)
Cement and Concrete Research ; 25 ; 29-38
1995
10 Seiten, 16 Bilder, 4 Quellen
Article (Journal)
English
Tonerdezement , Zusatzstoff , Zement , Natriumchlorid , Calciumchlorid , Natriumsulfat , Bindemittel , chemische Reaktion , Portlandzement , Dehnung , Schwindung , organische Verbindung , Hydratisieren , Saccharose , Wasserabbinden von Zement , hydraulisches Bindemittel , Rauminhalt , Lignosulfonat , Abbinderegulierer , Abbindebeschleuniger , Abbindeverzögerer , Calciumaluminatsulfathydrat , hydraulischer Zement , Zitrat , Zucker
| British Library Online Contents | 1995
| British Library Online Contents | 1994