Xabi Mendez Aretxabaleta
UPV / EHU
Ph.D. student, Department of Physics.
Atomistic simulations of Calcium Silicate Hydrate nucleation.
Green Concrete LTC
Laboratory for Trans-border Cooperation
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Ph.D. student, Department of Physics.
Atomistic simulations of Calcium Silicate Hydrate nucleation.
The environmental footprint of cement composites comes from three sources: CO2 emissions, energy demand and consumption of raw materials. The main contributor to the first one is the clinkerization process itself that involves high temperatures and the decarbonation of raw materials. Over the years, cement producers have made an important effort to improve the efficiency of the process, but they are arriving at a point where further improvement is no longer possible without a technological breakthrough. The activities of the LTC in this matter will focus mainly in the development of alternative production methods, like microwave clinkerization or hydrothermal treatments, and the improvement of clinker itself by the activation of less reactive phases or the promotion of the most reactive ones.
Cement composites are really awesome. First, they are very cheap and can be produced almost anywhere in the world using solely local materials. In addition, upon mixing of the solid components (mainly cement and aggregates) with water, a fresh cement composite is obtained. In such state, the material can even be pumped to the top of a skyscraper where it will acquire the shape of the mold where it is poured in. And then, after some time the material will harden at ambient conditions without human intervention. But the best of all is that the properties of the fresh and hardened material as well as the time it takes to become rock-solid can be tuned almost at wish. Nonetheless the development of cement composites with improved performance (strength, toughness, durability, thermal stability, etc.) never stops and it will be one of the main objectives of the LTC. The same applies to the development of novel functionalities (electrical conductivity, sensing capacity, self-healing, thermal properties, energy harvesting, etc.). Not to forget two of the main drivers of the last and coming years in Europe, the reduction of the environmental impact (and its quantification) and the digitalization of the industrial processes that will also be considered.
Additions, admixtures and additives are added during the process of the production of the cement or the cement composites to improve their performance. Therefore, the concrete of the future cannot be conceived without the development of processes (like supercritical fluids) for the synthesis of additions and additives with new or improved properties. Special focus will be placed on the development of nano-enabled material (nanoparticles and nanostructured materials) and superplasticizers; although other products might also be considered.
Cement matrix is a truly multi-scale structure whose features at the lower levels (nano-scale) have a substantial effect in the highest ones (macro-scale), and in the macroscopic properties. Furthermore, it is a “living” material whose properties may evolve for years due to a combination of physical and chemical phenomena. As a consequence, a deep study of the matrix requires of the participation of multidisciplinary teams that combine expertise on sample preparation, multi-scale simulation techniques, engineering tests, materials’ characterization methods, and so on.