A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
It is well known that the fluidity and the fluidity loss of fresh cement pastes are affected by the kind and the time of addition of organic admixtures. The influence of the time addition of two chemical admixtures, namely, melamine formaldehyde sulfonate (MFS) and naphthalene formaldehyde sulfonate (NFS), on the rheological properties of ordinary Portland and sulfate-resisting cement pastes through the first 120 min of hydration was investigated. The admixture addition was delayed by 0, 5, 10, 15, 20, and 25 min. Shear stress and apparent viscosity of the cement pastes were determined at different shear rates (3-146 s-1) and hydration times of 30, 60, 90, and 120 min. The concentration of Ca2+ and the combined water content of the cement pastes were determined after 120 min. Yield stress and plastic viscosity values were also determined by using the Bingham model. The results show that an increase in the addition time of the admixture reduces the shear stress, the yield stress, and the plastic viscosity of the cement pastes at the early ages (15 min) as well as at later early ages (120 min). The optimum delaying time of admixture addition is found to be 10-15 min. This time does not depend on the cement and superplasticizer type.
It is well known that the fluidity and the fluidity loss of fresh cement pastes are affected by the kind and the time of addition of organic admixtures. The influence of the time addition of two chemical admixtures, namely, melamine formaldehyde sulfonate (MFS) and naphthalene formaldehyde sulfonate (NFS), on the rheological properties of ordinary Portland and sulfate-resisting cement pastes through the first 120 min of hydration was investigated. The admixture addition was delayed by 0, 5, 10, 15, 20, and 25 min. Shear stress and apparent viscosity of the cement pastes were determined at different shear rates (3-146 s-1) and hydration times of 30, 60, 90, and 120 min. The concentration of Ca2+ and the combined water content of the cement pastes were determined after 120 min. Yield stress and plastic viscosity values were also determined by using the Bingham model. The results show that an increase in the addition time of the admixture reduces the shear stress, the yield stress, and the plastic viscosity of the cement pastes at the early ages (15 min) as well as at later early ages (120 min). The optimum delaying time of admixture addition is found to be 10-15 min. This time does not depend on the cement and superplasticizer type.
Influence of time addition of superplasticizers on the rheological properties of fresh cement pastes
Aiad, I. (author)
Cement and Concrete Research ; 33 ; 1229-1234
2003
6 Seiten, 16 Quellen
Article (Journal)
English
Influence of time addition of superplasticizers on the rheological properties of fresh cement pastes
| Online Contents | 2003
Influence of time addition of superplasticizers on the rheological properties of fresh cement pastes
| British Library Online Contents | 2003
Effect of some superplasticizers on the rheological properties of cement pastes
| Tema Archive | 1988
Influence of superplasticizers on rheological behaviour of fresh cement mortars
| British Library Online Contents | 2004