Cement-bound building materials, especially concrete, are indispensable today – but their production causes considerable CO2 emissions . By adding an additional coating to the surface, their durability and thus sustainability can be further improved. Research is being carried out on this worldwide – the Karlsruhe Institute of Technology (KIT) is considered a center of excellence. In a review article for the Royal Society of Chemistry, experts from KIT have now summarized the current state of research.
Overview of the performance of different methods
“We are comparing the performance of different surface coatings,” says Professor Frank Dehn from the KIT Institute of Concrete Structures and Building Materials Technology, one of the authors of the article. “They all have their advantages and disadvantages. Organic coatings such as epoxy resins are flexible and adaptable, but can decompose under environmental influences. Inorganic coatings such as silicate coatings are chemically resistant and durable, but less flexible and aesthetically limited.” Nanomaterials, i.e. extremely small particles with exceptional properties, could also be used, explains Dehn: “Graphene or nano-silica increase the mechanical strength of concrete and improve its resistance to environmental influences, sometimes even with self-healing properties.” Challenges, however, include uniform distribution, scalability for large-scale applications, and environmental concerns about the release of nanomaterials.
Coating with rare earths combines advantages
The authors see a particularly promising approach in incorporating rare earths into the concrete surface. This method can both increase the durability of concrete and combine other advantages of organic and inorganic coatings. “At KIT, for example, we are researching a europium coating that achieves water-repellent properties while at the same time keeping the environmental impact to a minimum,” says Dehn.
mhe, 03.07.2024
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