Flow conditions of fresh mortar and concrete in different pipes

Journal Article · Sun Nov 15 00:00:00 EST 2009 · Cement and Concrete Research

DOI:https://doi.org/10.1016/j.cemconres.2009.07.005· OSTI ID:21344731

Jacobsen, Stefan ^[1]; Haugan, Lars; Hammer, Tor Arne ^[2]; Kalogiannidis, Evangelos ^[1]

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1. Norwegian University of Science and Technology, Dept of Structural Engineering, Trondheim (Norway)
2. SINTEF Byggforsk AS Building and Infrastructure, Trondheim (Norway)

The variation in fresh concrete flow rate over the pipe cross section was investigated on differently coloured and highly flowable concrete mixes flowing through pipes of different materials (rubber, steel, acryl). First, uncoloured (gray) concrete was poured through the pipe and the pipe blocked. Similar but coloured (black) concrete was then poured into the pipe filled with gray concrete, flowing after the gray concrete for a while before being blocked and hardened. The advance of the colouring along the pipe wall (showing boundary flow rate) was observed on the moulded concrete surface appearing after removing the pipe from the hardened concrete. The shapes of the interfaces between uncoloured and coloured concrete (showing variation of flow rate over the pipe cross section) were observed on sawn surfaces of concrete half cylinders cut along the length axes of the concrete-filled pipe. Flow profiles over the pipe cross section were clearly seen with maximum flow rates near the centre of the pipe and low flow rate at the pipe wall (typically rubber pipe with reference concrete without silica fume and/or stabilizers). More plug-shaped profiles, with long slip layers and less variation of flow rate over the cross section, were also seen (typically in smooth acrylic pipes). Flow rate, amount of concrete sticking to the wall after flow and SEM-images of pipe surface roughness were observed, illustrating the problem of testing full scale pumping.

• OSTI ID: 21344731
• Journal Information: Cement and Concrete Research, Vol. 39, Issue 11; Other Information: DOI: 10.1016/j.cemconres.2009.07.005; PII: S0008-8846(09)00165-3; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0008-8846
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CONCRETES
CROSS SECTIONS
FLOW RATE
MORTARS
PIPES
RHEOLOGY
RUBBERS
SCANNING ELECTRON MICROSCOPY
STEELS
ALLOYS
BUILDING MATERIALS
CARBON ADDITIONS
ELASTOMERS
ELECTRON MICROSCOPY
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS
MICROSCOPY
ORGANIC COMPOUNDS
ORGANIC POLYMERS
POLYMERS
TRANSITION ELEMENT ALLOYS
TUBES