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Interaction between ettringite and a polynaphthalene sulfonate superplasticizer in a cementitious paste
It has been recognized that the interaction between a superplasticizer and C3A is crucial when controlling the rheology of Portland cement grouts, mortars and concretes. In spite of the fact that a great deal of research has been done to understand the exact nature of this interaction using different experimental techniques, there is not yet a clear understanding of all the basic principles which command that interaction. In an attempt to cast some complementary light in the type of interactions developed between C3A, Portland cement and a polynaphthalene sulfonate superplasticizer in the presence of calcium sulfate, the rheological behavior of a particular cementitious system in which only calcium aluminates or calcium sulfoaluminates hydrated phases could be formed has been studied. This study has shown that superplasticizer molecules are not only adsorbed on unhydrated cement phases but also and perhaps more on some of their hydrates. This adsorption on the hydrates slows down drastically or even stops the growth of ettringite germs. However, when all the initial superplasticizer molecules have been consumed normal growth of ettringite resumes. This interaction between superplasticizer molecules and ettringite can be used to explain the important water consumption in the early stages of mixing as well as the never answered question: where are all the superplasticizer molecules in a hardened concrete.
Interaction between ettringite and a polynaphthalene sulfonate superplasticizer in a cementitious paste
It has been recognized that the interaction between a superplasticizer and C3A is crucial when controlling the rheology of Portland cement grouts, mortars and concretes. In spite of the fact that a great deal of research has been done to understand the exact nature of this interaction using different experimental techniques, there is not yet a clear understanding of all the basic principles which command that interaction. In an attempt to cast some complementary light in the type of interactions developed between C3A, Portland cement and a polynaphthalene sulfonate superplasticizer in the presence of calcium sulfate, the rheological behavior of a particular cementitious system in which only calcium aluminates or calcium sulfoaluminates hydrated phases could be formed has been studied. This study has shown that superplasticizer molecules are not only adsorbed on unhydrated cement phases but also and perhaps more on some of their hydrates. This adsorption on the hydrates slows down drastically or even stops the growth of ettringite germs. However, when all the initial superplasticizer molecules have been consumed normal growth of ettringite resumes. This interaction between superplasticizer molecules and ettringite can be used to explain the important water consumption in the early stages of mixing as well as the never answered question: where are all the superplasticizer molecules in a hardened concrete.
Interaction between ettringite and a polynaphthalene sulfonate superplasticizer in a cementitious paste
Prince, W. (Autor:in) / Edwards-Lajnef, M. (Autor:in) / Aitcin, P.C. (Autor:in)
Cement and Concrete Research ; 32 ; 79-85
2002
7 Seiten, 12 Quellen
Aufsatz (Zeitschrift)
Englisch
Portlandzement , Naphthalin , Rheologie , Mörtel , Beton , Calciumverbindung , Hydrat , Adsorption , Ettringit , Superplastizität , Sulfonat , Zementpaste
| British Library Online Contents | 2002
Effects of fineness of cement on polynaphthalene sulfonate based superplasticizer-cement interaction
| British Library Online Contents | 2009
Effects of fineness of cement on polynaphthalene sulfonate based superplasticizer–cement interaction
| Online Contents | 2009