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Pro068

The rheological properties of polymer containing cementitious mixtures (PCC)



Author(s): S. Kubens, O.H. Wallevik, M. Puterman
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: 192 - 199
Total Pages: 8
Language: English


Abstract: 
Water based polymeric emulsions/dispersions are often used as additives for cementitious concrete mixtures to form what is called "Polymer Cement Concrete" (PCC). They are mainly used for the modification of mortars for repair purposes. The addition of polymeric emulsion has several advantageous effects on the fresh and hardened properties. In the fresh state the workability of the mixture is improved, probably due to the effect of the colloidal polymeric particles (prior to their coalescence) as well as due to the high content of the dispersed air bubbles. In the hard state the adhesion of the new concrete to old substrate is improved as well as its resistance to water and chloride penetration, probably due to the formation of polymeric "films" within the porous concrete.
It was the main aim of the project to study the rheological characteristics of fresh PCC mixtures in order to quantify the improvement in workability. First, the rheological properties yield value and plastic viscosity of the fresh mixtures were tested as a function of polymer content. Second, the changes in the rheological properties were measured as a function of time after water addition. It was shown that the addition of polymer emulsion to a cementitious mixture has a pronounced effect on rheological properties of the fresh mixture. Rheological properties are influenced by (1) the colloidal polymeric particles as well as by (2) the large amount of colloidal air bubbles formed during mixing due to the presence of stabilizing surfactants in the emulsion.
Polymeric emulsions reduce the yield value and the plastic viscosity of the mixtures. This enables us, at least from scientific and engineering aspects, to control the rheological properties of cementitious mixtures and adjust them to our needs.


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