IF MULTISCALE --> THEN MULTIDISCIPLINARY?

It's almost two years that I decide how to model the phenomenon of ASR in concrete structures. My choice is a multiscale material model based on poromechanics theory developed by Coussy, Dormieux, Ulm and further applied by Lemarchand and Charpin.

I like a lot this approach because you can bridge scales, the equations can be solved analytically and it proved to describe properly the mechanical behavior of concrete.

But today while reading the book titled "Mechanics and Physics of Porous Solid", I was asking to myself if it is indeed necessary to have a multidisciplinary approach to model this problem.

Can ASR in concrete be explained considering only mechanics? or do we need physics and chemistry too?

I don't have any answer at the moment, if you find one just let me know :)

Apparently, by crossing multiple scales you need to learn multiple disciplines!

Modeling ASR in concrete structures, it looks like finishing a puzzle. (picture from biotuesdays.com)

PhD Life: Formulating ASR Expansion

I came across this fun application on the web. And put our research topic to test..

So it was not that complicated after all...

ASR as hot topic at EURO-C Conference

The PAT-ASR team attended the last International Conference on Computational Modelling of Concrete and Concrete Structures, better know as EURO-C (http://euro-c.tuwien.ac.at/).
Intense and lively discussions were provoked by our presentation, as a results ASR was a "hot topic" of the conference.
Luckily we had the time to explore also the amazing conference venue: St Anton am Albereg (Austria) and enjoying the sun with many friends!
We also want to send our best wishes to Prof. Jan Rots, who is now an organizing member of this conference!

The proceedings.

The venue: St. Anton am Albreg, Austria.

Prof. Jan Rots appointed as organizing member of EURO-C conference by Prof. Gunther Meschke.

Computational Modelling of ASR Workshop

PAT-ASR team will present their work in a workshop on 9th April, 2014. This workshop is organised by Ruhr University. You can find more information about this workshop here.

We hope there will be some productive and informative discussions ahead of us. Hope to see you there.

Modelling efforts and control over realistic data

I have been recently busy with trying to improve damage model by implementing better ways to represent variety in material definitions. After finishing the analysis of NanoIndent results now we have the opportunity to assign this information (basically E-modulus and Strength values driven from hardness) for different phases in the system.

I recently introduced

• Random distribution based on Nano Indent test results - using mean and variance of data
• Triangular random generation of mesh with around 112000 elements to represent 10cm x 10cm sections
• Probabilistic distribution of reaction (in this case expansion) based on petrographic identification of reactive phases in aggregates (different for each mix design)
• and implementation of saturated cracks by updating the loading system while simulation is running (by introducing plastic behavior stage non elements stress strain curves)

Here are some representative images;

Histogram showing distribution of E values grouped by phases (Agg-Mortar-Bond-Void)

Heat map of E Mod values based on Digital image, Mesh geometry representing heterogeneity in aggregates and mortar

Initial Load elements with varied Intensities

Fracture evolution after 20000 simulation steps