Effect of metakaolin, superplasticiser, and viscosity modifying admixture on the rheological behaviour of grouts

Author(s): M. Sonebi
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: 183 - 191
Total Pages: 9
Language: English

Abstract: 
This paper reports a study carried out to investigate the effects of the replacement of cement by metakaolin (MTK), the dosage of superplasticiser (SP), and the dosages of viscosity modifying admixture (VMA) on the fluidity and flowability, the rheological behaviour, and the setting times. The grouts were developed with water-to-binder ratio of 0.40. Coaxial viscometer, mini-slump test, Marsh cone test, and Vicat test were used to assess the behaviour of fresh grouts.
The percentage of MTK, the dosage of SP, and the dosage of VMA were varied from 6% to 20%, 0% to 1.4% by mass of binder, and 0% to 0.06% by mass of binder, respectively. The results showed that the incorporation of MTK led to an increase in the yield stress and plastic viscosity and the flow time, and a reduction in fluidity. This reduction can be attributed to higher surface area of MTK and therefore resulted in a reduction of free water. The initial and final setting times were reduced by incorporating MTK. Adding SP has a greater effect on the fresh properties leading to a significant reduction of the rheological parameters, therefore improving the fluidity and flowability. This was mainly due to the better dispersion of cement particles. It was noted that SP significantly increased the setting times. However, the increase of VMA resulted in an increase in yield stress and plastic viscosity, and reduced the fluidity and the final setting time.

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