ASR Webinar (for free)

9th September 2021 from 13.00 to 15.00 (CET time)

Register for Zoom Link via Registration.

Alkali-silica reaction (ASR) causes cracking and with it substantial damages in concrete structures worldwide causing 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. This includes the understanding about various steps in the mechanisms of the reaction, the products formed and damage development. In an ASR-project funded by the Swiss National Science Foundation (SNF CRSII5_171018) a multidisciplinary approach was used to study ASR from the nano-to the metre-scale using dissolution experiments, thermodynamic modelling, structural analysis, 2-D characterization, 3D imaging and computational modelling. Six subprojects were conducted at four different institutes benefiting from the synergistic effects provided by a close collaboration. In the webinar we will present selected highlights of the project.

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Evolution of ASR products, doped with Cs, and respectively induced ASR cracks as observed by time-lapse X-ray tomography. Only the 2D digital cross-section from a small, 3D region of interest of the whole tomogram is shown. The Cs-doped ASR products appear as very bright because of their enhanced X-ray attenuation coefficient. For courtesy of Mahdieh Shakoori Oskooie, Concrete and Asphalt Lab., Empa

 

 

Presentations:

 

Aggregate dissolution, Mahsa Bagheri

Dissolution experiments and pore solution analysis provide insight on the effect of different ions on SiO2 dissolution.

 

Initially formed products, Solène Barbotin

Using a combination of focus ion beam and transmission electron microscopy the composition and structure of the initially formed ASR products are analyzed with a resolution down to the sub-micrometer range.

 

Atomic structure of ASR products, Guoqing Geng and Francesco Marafatto

The atomic structure of naturally formed and synthesized ASR products are identified by using spectroscopic techniques at synchrotrons.

 

Synthetic ASR products, Zhenguo Shi

The synthesis of amorphous and crystalline ASR products shows the effect of temperature on their structure and provides the base for a comparison with naturally formed products.

 

ASR products and cracking: a 4D view, Mahdieh Shakoorioskooie

The formation of ASR products and crack propagation are followed by high-resolution X-ray micro-tomography providing a 4D-view of the reaction.

 

Numerical modelling of mechanics, Emil Gallyamov

The numerical modelling of mechanics is based on realistic microstructure provided by 3D-analysis of crack formation.

Additional Information

Team

Project Leader

Andreas Leemann

Team

Barbara Lothenbach
Emil Gallyamov
Emmanuelle Boehm
Erich Wieland
Francesco Marafatto
Guoqing Geng
Jean-François Molinari
Karen Scrivener
Mahdieh Shakoori Oskooie
Masha Bagheri
Michele Griffa
Pietro Lura
Rainer Dähn
Solene Barbotin
Robert Zboray
Zhenguo Shi



Publication

Boehm-Courjault, E., Barbotin, S., Leemann, A., & Scrivener, K. (2020). Microstructure, crystallinity and composition of alkali-silica reaction products in concrete determined by transmission electron microscopy. Cement and Concrete Research, 130, 105988 (8 pp.)

Geng, G., Shi, Z., Leemann, A., Borca, C., Huthwelker, T., Glazyrin, K., Pekov, I. V., Churakov, S., Lothenbach, B., Dähn, R., & Wieland, E. (2020). Atomistic structure of alkali-silica reaction products refined from X-ray diffraction and micro X-ray absorption data. Cement and Concrete Research, 129, 105958 (11 pp.)

Geng, G., Shi, Z., Leemann, A., Glazyrin, K., Kleppe, A., Daisenberger, D., Churakov, S., Lothenbach, B., Wieland, E., & Dähn, R. (2020). Mechanical behavior and phase change of alkali-silica reaction products under hydrostatic compression. Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials, 76(4), 674-682

Leemann, A., Shi, Z., & Lindgård, J. (2020). Characterization of amorphous and crystalline ASR products formed in concrete aggregates. Cement and Concrete Research, 137, 106190 (10 pp.)

Leemann, A., Shi, Z., Wyrzykowski, M., & Winnefeld, F. (2020). Moisture stability of crystalline alkali-silica reaction products formed in concrete exposed to natural environment. Materials & Design, 109066

Shi, Z., Park, S., Lothenbach, B., & Leemann, A. (2020). Formation of shlykovite and ASR-P1 in concrete under accelerated alkali-silica reaction at 60 and 80 °C. Cement and Concrete Research, 137, 106213 (10 pp.)

Shi, Z., Leemann, A., Rentsch, D., & Lothenbach, B. (2020). Synthesis of alkali-silica reaction product structurally identical to that formed in field concrete. Materials and Design, 190, 108562 (9 pp.)