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Alkali-silica reaction in concrete

Applicant Leemann Andreas
Number 171018
Funding scheme Sinergia
Research institution Abteilung Beton / Bauchemie EMPA
Institution of higher education Swiss Federal Laboratories for Materials Science and Technology - EMPA
Main discipline Interdisciplinary
Start/End 01.05.2017 - 30.04.2021
Approved amount 1'719'202.00
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All Disciplines (3)

Discipline
Interdisciplinary
Material Sciences
Civil Engineering

Keywords (5)

alkali-silica reaction; concrete; microstructure; solubility; mechanical modeling

Lay Summary (German)

Lead
Bei der Alkali-Silica-Reaktion (ASR) im Beton reagieren Bestandteile des Zementes mit Mineralien der Gesteinskörnung. Wenn das Reaktionsprodukt durch Feuchtigkeitsaufnahme quillt, kann ein derart starker Druck entstehen, dass der Beton reisst. Solche Schäden sind weltweit zu beobachten. In der Schweiz sind mehrere hundert Betonbauten betroffen, unter anderem Brücken und Staudämme.
Lay summary

Inhalt und Ziel des Forschungsprojektes

Um die vorhandenen Wissenslücken zu füllen und damit die Effizienz von Gegenmassnahmen zu erhöhen, wird die ASR mit einem umfassenden Ansatz erforscht, der den Grössenmassstab vom Nanometer bis zum Bauwerk umfasst. Dabei werden chemische, strukturelle und mechanische Aspekte miteinbezogen. Der Einfluss von Ionen, die den chemischen Angriff auf die Gesteinskörnung und damit den Beginn der ASR beschleunigen oder hemmen, wird untersucht. Die Identifikation und Charakterisierung der ASR Produkte im Beton ermöglicht deren Synthese im Labor und damit ihre thermodynamische Modellierung. Dies wiederum erlaubt eine bessere Vorhersage der zu erwartenden chemischen Reaktionen. Das dreidimensionale Erfassen der Rissentwicklung im Beton wiederum ist die Grundlage für die nachfolgende mechanische Modellierung, die Rückschlüsse über das Bauwerksverhalten erlaubt.

 

Wissenschaftlicher und gesellschaftlicher Kontext des Forschungsprojektes

Die Vermeidung von Schäden durch ASR und der Umgang mit betroffenen Bauwerken basiert auf empirischen Ansätzen, weil das Wissen über den genauen Ablauf der Reaktion noch unvollständig ist. Die Ergebnisse sollen es erlauben, diese Situation zu verbessern und Folgekosten der ASR zu reduzieren.

Direct link to Lay Summary Last update: 03.04.2017

Responsible applicant and co-applicants

Employees

Project partner

Publications

Publication
Synthesis, characterization, and water uptake property of alkali-silica reaction products
Shi Zhenguo, Geng Guoqing, Leemann Andreas, Lothenbach Barbara (2019), Synthesis, characterization, and water uptake property of alkali-silica reaction products, in Cement and Concrete Research, 121, 58-71.
Synthesis and characterization of alkali-silica reaction products
Shi Zhenguo (2019), Synthesis and characterization of alkali-silica reaction products, RILEM Publications S.A.R.L., Paris, France.
Microstructural analysis of ASR in concrete - accelerated testing versus natural exposure
LeemannAndreas (2019), Microstructural analysis of ASR in concrete - accelerated testing versus natural exposure, RILEM Publications S.A.R.L., Paris, France.

Collaboration

Group / person Country
Types of collaboration
centre interdisciplinaire de microscopie électronique (CIME), EPFL Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
Empa, aboratory for Nanoscale Materials Science Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Federal Office of Energy Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Industry/business/other use-inspired collaboration
Karlsruhe Institute of Technology Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
University of Texas United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
Norwegian University of Science and Technology (NTNU) Norway (Europe)
- in-depth/constructive exchanges on approaches, methods or results
Oregon State University, College of Engineering United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
University Aarhus Denmark (Europe)
- in-depth/constructive exchanges on approaches, methods or results
École normale supérieure de Cachan, Civil Engineering France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel
Lawrence Berkeley National Laboratory United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
FraMCoS-X : Fracture Mechanics of Concrete and Concrete Structures Talk given at a conference Experiments-based multi-scale modeling of the alkali-silica reaction in concrete 24.06.2019 Bayonne, France Gallyamov Emil;
FraMCoS-X : Fracture Mechanics of Concrete and Concrete Structures Talk given at a conference Meso-scale finite element modeling of Alkali-Silica-Reaction (ASR) in concrete 24.06.2019 Bayonne, France Rezakahani Roozbeeh;
Euroseminar of Microscopy Applied on Building Materials Talk given at a conference Characterization of initial ASR products by SEM, FIB and STEM-EDX 20.05.2019 Toronto, Canada Barbotin Solène; Scrivener Karen; Leemann Andreas;
International Symposium on Cement-based Materials for Nuclear Wastes Poster Properties of alkali-silica reaction products 24.10.2018 Avignon, France Shi Zhenguo; Leemann Andreas;
Cement and Concrete Science Conference Talk given at a conference Dissolution of concrete aggregates 10.09.2018 Coventry, Great Britain and Northern Ireland Scrivener Karen; Leemann Andreas; Bagheri Mahsa;
Cement and Concrete Science Conference Talk given at a conference Characterization of early stage reaction prodcut using STEM-EDX and electron diffraction 10.09.2018 Coventry, Great Britain and Northern Ireland Leemann Andreas; Barbotin Solène; Scrivener Karen;


Awards

Title Year
Best Poster Award NUWCEM, Avignon, France 2018

Associated projects

Number Title Start Funding scheme
143782 Multi-contrast X-ray imaging of water and microstructure in cement-based materials 01.02.2013 Project funding (Div. I-III)
153044 Synthetic Calcium Silicate Hydrates -from synthetic synthesis to atomistic modelling and growth kinetics for early age strength and eco friendly cement & concrete 01.07.2014 Project funding (Div. I-III)
162572 Enhancing multi-contrast X-ray imaging of water and microstructure in cement-based materials by exploiting the dark-field channel and improving the temporal resolution 01.02.2016 Project funding (Div. I-III)
162342 Thermodynamische und spektroskopische Untersuchungen der Fe und S Speziation in anoxischen Zementsystemen 01.04.2016 Project funding (Div. I-III)
157738 Muscat: Multiscale X-ray Computed Tomography 01.11.2015 R'EQUIP
169014 Effect of aluminum on C-S-H structure, stability and solubility 01.03.2017 Project funding (Div. I-III)
156412 Detailed understanding of metal adsorption on clay minerals obtained by combining atomistic simulations and X-ray absorption spectroscopy 01.01.2015 Project funding (Div. I-III)

Abstract

In the alkali-silica reaction (ASR) the alkaline pore solution of concrete reacts with silicon oxide present in rocks used as concrete aggregates. The formed reaction product is able to imbibe water and to swell. This generates stress in the concrete causing cracking. As the reaction proceeds very slow, the first damages are usually observed 10-20 years after the concrete structures have been built. Substantial damages are observed worldwide. In Switzerland, several hundreds of structures, including bridges and dams, are affected, causing substantial costs due to repair or replacement. Although ASR is one of the major focal points of concrete research since the first cases were reported in the 1940's, our knowledge is still not sufficient to understand various aspects of the reaction. Due to a lack of in-depth knowledge about the mechanisms of the reaction and about how damage develops, ASR mitigation and management of affected structures is still based on a purely empirical approach. In order to improve this situation, a breakthrough in the understanding of ASR is needed. Such an ambitious goal can only be reached by using a multidisciplinary and multiscale approach linking chemical and mechanical aspects of ASR. The broad range of expertise needed is covered by the participating institutes. They bring together the fields of chemistry and thermodynamic modelling, structural analysis of reaction products, 2-D materials characterization, 3D X-ray tomography and mechanical modelling. In order to benefit optimally from this broad range of expertise, the proposed six subprojects are closely linked.In subproject I, the initial dissolution of SiO2 by synthesized concrete pore solutions is studied to identify the mechanism by which the ASR-suppressing ions aluminum and lithium influence the dissolution of aggregates and with it the initiation of ASR. The analysis of the composition and structure of the initial ASR products in subproject II will improve the understanding on both their formation and their subsequent expansion and establish a link to the resulting damage in concrete. The application of synchrotron-based techniques in subproject III will allow new insight on the structure of amorphous and crystalline ASR products formed under different boundary conditions, ultimately helping to explain the observed expansion behavior. A prerequisite for the prediction of occurrence and kinetics of ASR are the determination of solubility products and the use of thermodynamic modelling covered in subproject IV. The ongoing monitoring of crack formation during ASR development by non-destructive 3D-analysis in subproject V will make crack formation visible and provide essential input for subproject VI. The consequences of ASR on the behavior of structures will be investigated in subproject VI by mechanical modelling based on realistic microstructures provided by 3D-analysis of crack formation.The participating research groups represent a so far unique combination of expertise in the field of ASR, ensuring a multidisciplinary and multiscale approach. As a result, the participating students, researchers, institutes and the Swiss science community in this field will greatly benefit from the project.
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