Author: Anna Chaliasou -
Who is a concrete geek: The concept of cement and concrete has been around for decades, one could even claim for millennia if Roman concrete is considered. Contrary to the common belief though, the long-standing presence of Portland cement in our lives isn’t analogous to our knowledge about it. Until the past century, when research started investigating cement’s intrinsic mechanisms, trial and error had been the only ways to manipulate its’ properties. Given its’ heterogeneous nature, there are still things to discover about the second most commonly used material in the world. All those then, who are fascinated by its potential and eager to unveil its secrets (including myself) are the ones to be called concrete geeks.
The meeting: This April I was given the opportunity to attend the “LC3 Doctoral School: Characterisation methods of blended cements” at École Polytechnique Fédérale de Lausanne - EPFL. It took place at the Laboratory of Construction Materials, Department of Materials of EPFL and it was organised by the team of Professor Karen Scrivener, Head of the laboratory and Editor in Chief of Cement and Concrete Research. From the 3rd until the 6th of April, approximately 30 participants from all over the word, from both the industry and academia, were brought together. Their common interest: cement and concrete science.
How I got there: I wouldn’t have been present at this event, had it not been for the two organisations that supported me. One was the Institute of Minerals, Materials and Mining (IOM3) with the Andrew Carnegie Research Fund and the second was the Armourers & Brasiers Gauntlet Trust with the Travel Grant for PhD Students for Conferences and Industrial Placements.
Content of event: The Doctoral School was an intensive training course about cement and concrete science, including lectures and practical sessions. The lectures covered a wide range of topics including both scientific aspects of cement and concrete science as well as geo-economic factors affecting its use worldwide.
A topic that received a lot of attention was the use of material characterisation techniques for cement and concrete. Techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) are commonly applied techniques for material characterisation. Although they are popular in a range of other fields, the intrinsic structure of cement makes it difficult to exploit their full potential. Therefore, appropriate application and interpretation is a burning issue in the research to obtain interpretable results. Other topics discussed were about common issues relating to concrete such as chemical shrinkage, creep, durability along with mitigation measures and principles of rheology and mix design.
The practical sessions took place at the facilities of the Department of Materials at EPFL. The sessions were hands-on and covered a range of techniques. More specifically, SEM and XRD for identification of cement hydration reaction products and calorimetry for investigation of reaction evolution. Also, methodologies for sample preparation for all these techniques, with special focus on samples for SEM, were demonstrated. During the practical sessions, the participants were given the opportunity to use the laboratory equipment and apply some of the demonstrated techniques themselves. Also, tours on the material preparation, concrete & structures and analysis laboratories took place. During those tours, the participants had the opportunity to discuss with PhD students, academic staff and technicians. This created an opportunity to explore areas of common interests and exchange research information. Finally, two events, a dinner and farewell lunch, provided additional opportunities for additional socialising amongst the organising team and the participants outside the course’s context.
My experience: The lecture “Cement and concrete in building worldwide” by Professor Karen Scrivener put in context how the earth mineralogy and geographic distribution of raw materials affect the use of cement and supplementary cementitious materials worldwide. Given the dispute about the environmental footprint of Portland cement, the availability of alternative supplementary materials is a burning issue in cement research.
The second session of lectures delivered by Professor Scrivener, “Cement hydration, kinetics of the reaction, aluminates & microstructure and final phases”, was an in-depth analysis of the hydration reaction of cement, the products and its kinetics. I found this lecture very beneficial and many of my questions were answered as I got a clearer understanding of the chemical processes I am investigating. Also, I had the opportunity to discuss some particularities of my own project and obtain valuable advice and material from the professor. Karen Scrivener is well renowned in the field of cement and concrete science for her research. Therefore, having the opportunity to discuss with her, opened new horizons for my work.
Two sessions that proved very beneficial for my project were the lectures “X-ray diffraction applied to cement” by Dr Ruben Snellings and “Porosity and microstructure characterisation” by Francois Avet. In the latter, the use of mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM) for cement and concrete were discussed. Dr Snellings has been awarded the 2016 Gustavo Colonnetti Medal for his contribution to the field construction materials, while François Avet is now completing his PhD research in cement characterisation at EPFL. As mentioned above, the application of such techniques in the context of concrete is a matter needing attention. Given that the nature of the system I am investigating is much more complex than common concrete systems, I had the opportunity to discuss aspects of my project and get advice on how to manipulate the techniques to overcome the barriers I am facing.
The rest of the lectures, “Shrinkage and creep” by Julien Ston, “Concrete Durability” by Dr Hamed Maragheschi about deterioration reactions occurring in concrete elements (carbonation, chloride attack & alkali silica reaction) and “Rheology and Mix design” by Dr Aurelie Favier, were very enlightening. All the presenters were willing to share their knowledge, discuss aspects of my project relating to their field of expertise, provide advice and reading material or even establish communication with members of their team.
On top of the actual training, the opportunity to interaction with the rest of the participants helped broaden my view. The diversity of backgrounds, various places around the word and the mix of academics and professionals made the interaction very interesting and fruitful. We were given the opportunity to discuss about grounds of common interest, diversity of methodologies and approaches and of course exchange advice (as proper concrete geeks would do).
Outcome: Overall, I could conclude that I am very grateful to be given the opportunity to take part in the LC3 Doctoral School at EPFL. I had the opportunity to meet well renowned experts in my field, interact with people sharing the same interest and problems, get introduced to different perspectives and finally enrich my knowledge. The benefits are not to be counted only in terms of knowledge but also the opportunity to prepare the ground for future collaborations and develop as a researcher through the exchange of information with my peers.
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