Experimental approach on a moving formwork. (8th February 2021)

• Record Type: Journal Article
• Authors: Craipeau, T.; Toussaint, F.; Perrot, A.; Lecompte, T.
• Is Part Of: Construction & building materials. Volume 270(2021)
• Publication Date: 2021-02-08
• Subjects: Slipforming -- Friction -- Jansen's model -- Pore water pressure -- Terzaghi's equation; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2020.121472
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: New setup examining friction behavior between cement-based materials/formwork. In-house sensors: interfacial pore water pressure, interfacial local frictional sensor. Modeling approach based on coupling a Janssen's model with interface yield stress. Different mix-design parameters: water/air content, granular packing, surface tension. Abstract: In a slipforming process, concrete is continuously poured and the formwork simultaneously raised so that the older concrete on the bottom supports the fresher on the top after a few hours of hydration. The objective of the present study is to examine the evolution of the concrete/formwork interface at very early age. An experimental device was designed to measure the evolution of the friction at this interface during the first hydration period. With cement hydration and thus water consumption, pore water pressure decreases and creates suction, which could increase granular stress on the formwork. The role of pore water pressure on formwork friction is investigated. The effect of mix-design parameter such as air content is described. Finally, a model that is able to predict the friction force at very early age (up to the initial setting time) is proposed.