Dunkelverfärbungen im unteren Wandbereich von Sichtbetonflächen

Wechselwirkungen zwischen Schalungsvibrationen und Betontechnologie

authored by: Macielle Deiters, Tobias Schack, Matthias Fischer, Denis Kiltz, Michael Haist
Abstract: Dark discoloration in the lower wall area on exposed concrete surfaces – Interactions between formwork vibrations and concrete technology. The use of exposed concrete construction represents an irreplaceable architectural design element, particularly for the creation of represented concrete buildings. Despite an increasing variety of design possibilities, such as with colored or textured elements, many planners and builders still prefer smooth and uniformly light-colored exposed concrete surfaces created for using in-situ concrete constructions. Despite significant and technical advancements, optical irregularities like dark discolorations, are repeatedly observed in the production of such exposed concrete components. These discolorations cannot be fully explained by existing scientific approaches and cannot be technically eliminated so far. As a part of a research project jointly conducted by the Institute of Building Material Science of Leibniz University of Hannover and the German Concrete and Construction Technology Association (Deutscher Beton- und Bautechnik-Verein E. V.), the mechanisms leading to dark discolorations in lower wall areas of exposed concrete components were systematically investigated. In Particular, a direct influence of formwork vibrations in interaction with concrete technological properties was identified as a central factor for dark discolorations. The likelihood of such discolorations significantly increases when stiffening concrete (i. e. concrete whose age is approaching the initial setting time) are either directly or indirectly set into vibration by the formwork. A significant interaction was found between the timing of vibration initiation, the concrete technological properties and the vibration parameters (frequency and amplitude).
Organisation(s): Institute of Building Materials Science
External Organisation(s): Deutscher Beton- und Bautechnik-Verein e.V.
Type: Article
Journal: Beton- und Stahlbetonbau
ISSN: 0005-9900
Publication date: 20.09.2024
Publication status: E-pub ahead of print
Peer reviewed: Yes
ASJC Scopus subject areas: Building and Construction
Electronic version(s): https://doi.org/10.1002/best.202400059 (Access: Closed)

BibTeX

@article{d2f247e2e0a04944bb8dd48f84ff47d8,
title = "Dunkelverf{\"a}rbungen im unteren Wandbereich von Sichtbetonfl{\"a}chen: Wechselwirkungen zwischen Schalungsvibrationen und Betontechnologie",
abstract = "Dark discoloration in the lower wall area on exposed concrete surfaces – Interactions between formwork vibrations and concrete technology. The use of exposed concrete construction represents an irreplaceable architectural design element, particularly for the creation of represented concrete buildings. Despite an increasing variety of design possibilities, such as with colored or textured elements, many planners and builders still prefer smooth and uniformly light-colored exposed concrete surfaces created for using in-situ concrete constructions. Despite significant and technical advancements, optical irregularities like dark discolorations, are repeatedly observed in the production of such exposed concrete components. These discolorations cannot be fully explained by existing scientific approaches and cannot be technically eliminated so far. As a part of a research project jointly conducted by the Institute of Building Material Science of Leibniz University of Hannover and the German Concrete and Construction Technology Association (Deutscher Beton- und Bautechnik-Verein E. V.), the mechanisms leading to dark discolorations in lower wall areas of exposed concrete components were systematically investigated. In Particular, a direct influence of formwork vibrations in interaction with concrete technological properties was identified as a central factor for dark discolorations. The likelihood of such discolorations significantly increases when stiffening concrete (i. e. concrete whose age is approaching the initial setting time) are either directly or indirectly set into vibration by the formwork. A significant interaction was found between the timing of vibration initiation, the concrete technological properties and the vibration parameters (frequency and amplitude).",
keywords = "compaction, concrete technology, dark discoloration, exposed concrete, vibration of formwork",
author = "Macielle Deiters and Tobias Schack and Matthias Fischer and Denis Kiltz and Michael Haist",
note = "Publisher Copyright: , Ernst und Sohn. All rights reserved.",
year = "2024",
month = sep,
day = "20",
doi = "10.1002/best.202400059",
language = "Deutsch",
journal = "Beton- und Stahlbetonbau",
issn = "0005-9900",
publisher = "Wiley-Blackwell",
}