Rheological properties of Portland cement slurries containing biopolymer: effects of the variation of the water/cement ratio, ageing and biopolymer concentration

Author(s): U.T. Bezerra, A.E. Martinelli
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: 200 - 207
Total Pages: 8
Language: English

Abstract: 
This work reports the rheological properties of cement slurries containing a biopolymer. Results show that whereas the Bingham model easily assesses the rheological behavior of such slurries, the Herschel-Bulkley model best fit the results, because the graphics precisely present the yield stress following a defined curve, contrary to the Bingham model. The slurries were evaluated by factorial planning: water/cement ratio, ageing and biopolymer concentration. For the plastic viscosity, it is observed that the biopolymer affect the results, suggesting that the polymer chelates the calcium ions of cement and immobilizes the water molecules. It was found that the water/cement ratio influenced the results. Ageing showed no effect on the plastic viscosity, which means that the large hydrated particles do not prevent the flow of the slurry in the viscometer. As for the yield stress, the results show that all the evaluated factors influenced this parameter; however, the addition of a dispersant can reduce the values obtained. Therefore, the addition of biopolymer did not significantly interfere with the rheological properties of cement slurries. After the first three setting days, which is an important period in the development of the final microstructure of the hardened slurry, the mechanical strength of the slurries significantly increased, as suggested by previous studies, thus reducing the occurence of cracks in this period.

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