Mechanisms for the changes in fluidity and hydration kinetics of grouts after mixing

Author(s): K. Takahashi, T. Bier
Paper category: Conference
Book title: Rheology and processing of Construction Materials – 7th RILEM International Conference on Self-Compacting Concrete and 1st RILEM International Conference on Rheology and Processing of Construction Materials
Editor(s): Nicolas Roussel and Hela Bessaies-Bey
Print ISBN: 978-2-35158-137-7
e-ISBN: 978-2-35158-138-4
Publisher: RILEM Publications SARL
Pages: 213-220
Total Pages: 8
Language: English

Abstract: 
Mixing and pumping both exert mainly shearing action to adversely affect rheology and hardening properties of cement-based grouts. However, little research conducted on the effects of shearing energies has focused on the mechanisms for such typical changes. This study examines the effects of mixing periods on fluidity and hydration kinetics of grouts with different dispersion conditions adjusted for super plasticizer doses. Our results identify hydration acceleration and a loss in fluidity occurring with increasing mixing energies, even in the case of fully dispersed grouts. From these findings, the mechanism responsible for hydration acceleration is pinpointed as the increase of active surface area to dissolution due to the destruction of the protective superficial layers of cement particles as well as a transition from flocculation to dispersion. The creation of new surfaces leads to further consumption of active super plasticizer in solution phase and to subsequent degrading changes in fluidity.

Online publication: 2013
Publication Type: full_text
Public price (Euros): 0.00