Resistance classes for concrete - Consideration of a promising new concept

Against the background of climate change, of environmental considerations and discussions about public investment, sustainability has become an important issue in building design. Current progress with highly durable concrete promises positive sustainability effects. Whether these can really be implemented remains however questionable since the improvement of durability could be balanced by an increased material demand. This brings into play the concept of resistance classes for concrete in combination with performance-based design, which could offer a more transparent and flexible approach compared to the current simplified durability concept based on concrete cover and exposure classes. Although the new approach has already delivered important scientific findings, aspects like its practical usability, adaptation flexibility and the robustness of the models will have to be dealt with in more detail before the concept can be implemented in practice. This article provides an overview of the current state of research and describes the most significant unsolved questions with regard to structural design and climate neutrality.