74. Formwork pressure when using SCC - A doctoral project

Title: 74. Formwork pressure when using SCC - A doctoral project
Author(s): P. Billberg
Paper category : conference
Book title: 5th International RILEM Symposium on Self-Compacting Concrete
Editor(s): G. De Schutter and V. Boel
Print-ISBN: 978-2-35158-047-9
e-ISBN: 978-2-35158-088-2
Publisher: RILEM Publications SARL
Publication year: 2007
Pages: 491 - 496
Total Pages: 6
Nb references: 6
Language: English

Abstract: A project has been carried out aiming at deepening the understanding of how the structural behaviour of SCC at rest influences the formwork pressure. The project is based on four hypotheses stating: (1) the thixotropic mechanisms originate from concrete fluid phase (2) the total structural change with time at rest is a function of a reversible, thixotropic, structural build-up and an irreversible change of consistency with time, (3) the magnitude of the structure can be represented by the maximum elastic stress the fresh material can withstand before the structure breaks and finally (4) this structural build-up influences the formwork pressure. The methodology used is based on using a rheometer to perform stress-strain measurements at various times at rest, enabling a recording of the material transformation from elastic to plastic and further on to viscous. To quantify the irreversible structural change with time, conventional rheology is measured before and after the rest. For the form pressure measurements, an instrumented steel pressure tube is used which enables also to simulate various casting heights and rates. The results verify all four hypotheses.

Online publication: 2009-06-16
Publication type : full_text
Public price (Euros): 0.00