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Robustness of cement suspensions - superplasticizer adsorption, particle separation and interparticle forces



Author(s): D. Lowke, P. Schiessl
Paper category: Symposium
Book title: 3rd International RILEM Symposium on Rheology of Cement Suspensions such as Fresh Concrete
Editor(s): O.H. Wallevik, S. Kubens, S. Oesterheld
ISBN: 978-2-35158-091-2
e-ISBN: 978-2-35158-092-9
Pages: 45 - 54
Total Pages: 10
Language: English


Abstract: 
Rheological properties and robustness of cement based suspensions are affected by the surface properties of particles, the properties of the liquid phase and the adsorbed polymers. To understand the interaction between these parameters and robustness of cement based suspensions the surface forces of the colloidal powder particles were considered. Three surface forces are taken into account - the attractive van der Waals forces, the repulsive double layer forces and the polymer induced steric forces. A theoretical basis for the evaluation of these forces in cement based suspensions is given. Within the experimental program the superplasticizer adsorption was determined for cement and ground limestone suspensions. Rheological measurements were performed to determine yield stress, thixotropy and the robustness of the rheological properties with respect to water overdosage. The results indicate a strong correlation between the water-/powder ratio, polymer adsorption and robustness. A model based on the evaluation of interparticle forces is presented to explain the robustness of the investigated mortars.


Online publication: 2009
Publication Type: full_text
Public price (Euros): 0.00