Katerina Ioannidou: From soft physics to concrete applications

A physicist specializing in concrete. Katerina Ioannidou admits that her research subject may come as a surprise. I thought it was very strange to be offered a thesis on the physics of cement ", recalls the researcher at the Laboratory of Mechanics and Civil Engineering, an ordinary material that she initially found too " exotic". But in the end, it's a fascinating material, very difficult to study and model, because you're never sure what you're working with ", she adds. This complexity is due to the sheer number of chemical reactions that take place in cement. The subject doesn't suit physicists, who prefer more predictable materials.

It was good fortune for him to continue exploring such complex materials. His understanding of their fundamental principles, modeled using statistical physics, earned him a CNRS bronze medal in 2024. His work is of interest because it is applicable to solutions for energy storage and_CO2 sequestration in cement. These are enormous industrial challenges, given that cement - the main component of concrete to which it is used as a binder - is the world's most consumed material. Its production generates 7% of the world's carbon dioxide emissions ( GCCA figures). To reduce this footprint, Katerina Ioannidou's work explores two avenues. Firstly, to create multifunctional building materials capable of storing energy.

Turning a concrete block into a battery

" For example, concrete lamps capable of storing energy produced by renewable energies and releasing it in the form of light," explains the physicist who began working on a super-capacitor concrete while a post-doc at the Massachusetts Institute of Technology (MIT) in Boston, in an international laboratory associated with the CNRS.

Thanks to the Momentum program launched in 2016, it is funding its project on concretes for energy-autonomous buildings. The idea is to use the porosity of cement by filling it with carbon black (or porous carbon), an inexpensive material whose properties make it possible to turn a concrete block into a battery. More precisely, the conductivity and porosity of carbon black allow it to be charged with ions, enabling electrochemical energy storage. This work was rewarded with a patent in 2017 and a position at the CNRS the following year.

Katerina Ioannidou is also working on another application,_CO2 sequestration in cement. The idea is to accelerate the carbonation process, a reaction with carbon dioxide that fixes it. Although this reaction occurs naturally, it is very slow. Thanks to the characteristics of carbon black added to cement, the reaction no longer takes decades, but only a few weeks. " These solutions have yet to be deployed on a large scale, and they won't solve everything. But they already have the merit of showing industrialists the scale of the problem," comments the woman who is working in collaboration with the Greek cement manufacturer Titan on nanoporous cements.

The physics of soft matter

Since completing her thesis in a civil engineering department at ETH Zurich, the researcher has been confronted with the industrial application of her research. In fact, she recounts how she happily swapped the theoretical physics of her Master's degree at Utrecht University in the Netherlands for soft matter physics. " Applied physics in which I can project my numerical modeling work onto the materials around me. At first, discussions with engineers weren't easy, as they're less interested in understanding mechanisms than in practical results. But these exchanges have been a very good exercise in finding a common language. "

The woman who began her career with a tour of Europe, including a bachelor's degree in her native Greece, a master's in the Netherlands, a thesis in Switzerland and a foray into the USA before coming to work in France, finds the French research scene unique: " Here, I really appreciate the collaboration between male and female researchers. The main drawback, however, is access to funding.