Damage to Concrete Structures

Schutter, Geert De

doi:10.1201/b12914

Cited by 16 publications

(13 citation statements)

References 62 publications

(107 reference statements)

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“…Nach Kenntnis der Autoren ist die Rissfortpflanzung aus der Eisschicht in den Beton nicht nachgewiesen. Im englischsprachigen Raum hat das Modell dennoch eine beträchtliche Anerkennung gefunden .…”

Section: Schadensmodelleunclassified

Frost‐Tausalz‐Angriff auf Beton

Müller

Ludwig

Ehrhardt³

2019

Beton und Stahlbetonbau

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Wiederholte Frost‐Tau‐Wechsel können in Zusammenhang mit der Einwirkung von Feuchtigkeit und Tausalzen eine Schädigung der Betonoberfläche durch Abwitterungen verursachen. Der Frost‐Tausalz‐Widerstand von Beton wird momentan vorwiegend über deskriptive Ansätze gewährleistet, also indirekt über Vorgaben zur Betonzusammensetzung und Nachbehandlung. Infolge des stetigen Wandels von Baustoffen und Bauweisen und dem damit verbundenen Verlust des Erfahrungshintergrunds wird mittelfristig das Performancekonzept auf der Basis genormter Prüfverfahren das deskriptive Konzept ablösen. Es ist zu erwarten, dass darüber hinaus auch für den Bereich des Frost‐Tausalz‐Angriffes probabilistische Modelle für eine Lebensdauerbemessung notwendig werden. Unverzichtbare Basis dafür ist ein tiefergreifendes Verständnis für den zugrunde liegenden Schadensmechanismus. Obwohl der Frost‐Tausalz‐Angriff auf Beton seit vielen Jahrzehnten wichtiger Gegenstand der Forschung zur Betondauerhaftigkeit ist und eine Vielzahl von Schadensmodellen dazu entwickelt wurde, konnte eine widerspruchsfreie Beschreibung des Angriffes bisher nicht gegeben werden. In der jüngeren Vergangenheit wurden neue Schadenstheorien aufgestellt, die für sich in Anspruch nehmen, den Frost‐Tausalz‐Angriff umfassend abzubilden. Im Rahmen dieses Beitrags erfolgt eine kritische Auseinandersetzung mit diesen neuartigen, aber auch mit den „historischen“ Modellen, um erste Grundlagen für eine Modellbildung des Frost‐Tausalz‐Angriffes zu legen.

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Section: Schadensmodelleunclassified

Frost‐Tausalz‐Angriff auf Beton

Müller

Ludwig

Ehrhardt³

2019

Beton und Stahlbetonbau

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“…There are still many gaps in knowledge that need to be explored in order to adequately resolve these issues. Due to the high fluidity of SCC, one of the main challenges cited by contractors is the increase in formwork pressure and leakage between formwork panels [1]. To avoid formwork collapse or excessive surface defects, stiffer forms and supplementary sealing actions are required, making the use of SCC unappealing.…”

Section: Introductionmentioning

confidence: 99%

“…Leakage of cement grout at the formwork joints could result in poor surface quality or even honeycombing in more severe cases. Water and fine particles (cement, powders and fine sand) are drained away, leaving unacceptable surface defects [1]. The unfortunate thing is that these sub-standard results are only discovered after the formwork is removed and the concrete has already set.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Formwork Tightness as a Function of Rheological Properties of SCC

et al. 2019

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Several studies relating formwork pressure to rheology exist, however the relationship between rheology and leakage through formwork joints remains to be investigated. In practice, standard documents are used to define formwork tightness requirements, typically using a qualitative approach. To try bridge this gap in knowledge, we developed a test setup to study tightness of formwork joints under pressure as a function of varying rheological properties. Coupled with standard rheology tests, this new test setup provides means of linking flow rate, formwork pressure, flow area, and the rheological properties. The study seeks to provide insight on measurable governing parameters and thus inform formwork tightness requirements in a more quantifiable manner. This paper presents a test setup designed to study the flow of fresh paste through small openings. It highlights a preliminary study on the pressure-driven flow of limestone paste through a bottom orifice in a cylindrical container. While this new device may not be directly representative of the actual conditions in formwork, it provides a good base for a fundamental study that can then be extrapolated to a more representative test operation. Preliminary results show a linear relationship between the flow rate and the applied pressure. The results also show that increasing the flow area by a factor of 2.33 had a higher impact than an increase in yield stress and viscosity by a factor of 2.54 and 3.80 respectively. However, more tests need to be carried out to obtain clear trends.

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“…Damage to concrete structures mainly occurs because of inadequate management, incorrect maintenance, overloading, exposure to chemical components, climatic factors, and also extra loads such as earthquakes [1]. As mentioned by Nikoo et al [2], earthquakes are the most devastating of these factors.…”

Section: Introductionmentioning

confidence: 99%

Determination of Damage in Reinforced Concrete Frames with Shear Walls Using Self-Organizing Feature Map

Nikoo

Sadowski

Khademi

et al. 2017

Applied Computational Intelligence and Soft Computing

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The paper presents the use of a self-organizing feature map (SOFM) for determining damage in reinforced concrete frames with shear walls. For this purpose, a concrete frame with a shear wall was subjected to nonlinear dynamic analysis. The SOFM was optimized using the genetic algorithm (GA) in order to determine the number of layers, number of nodes in the hidden layer, transfer function type, and learning algorithm. The obtained model was compared with linear regression (LR) and nonlinear regression (NonLR) models and also the radial basis function (RBF) of a neural network. It was concluded that the SOFM, when optimized with the GA, has more strength, flexibility, and accuracy.

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Damage to Concrete Structures

Abstract: This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use.

Cited by 16 publications

References 62 publications

Frost‐Tausalz‐Angriff auf Beton

Frost‐Tausalz‐Angriff auf Beton

Experimental Study of Formwork Tightness as a Function of Rheological Properties of SCC

Determination of Damage in Reinforced Concrete Frames with Shear Walls Using Self-Organizing Feature Map

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