In line with climate goals, the aim is to develop concrete types for which less CO₂ is emitted during production. Various visions for mixture design are considered in this regard. Some of these visions include: the use of waste materials as partial replacement of traditional cement, binder development based on alkali activation, binder development based on geopolymer systems, ... When developing these different concrete types, it is important to gain a fundamental understanding of the development of the microstructure of the hardened concrete. What is the role of the different raw materials? What is the role of the chemical and mineralogical composition of the different raw materials? Exactly what structure is formed during curing of the developed concrete. Mechanical properties, deformation behaviour and durability properties are decisive for practical use and should be investigated starting with mechanical behaviour and deformation behaviour.