Life-cycle assessments have established themselves as an important aid for evaluating sustainability. A so called Type III environmental declaration for ready-mixed concrete can be found on the internet at www.beton.org. Fig. 1 shows the composition of various types of concrete. Their environmental impact is shown in fig. 2. However, it is not possible to evaluate sustainability in these terms as the composition of the concrete – and thus the compressive strength class – has implications not just for ecological, but also for economic and, in the broader sense, social product properties. For example, using stronger concrete types makes it possible to work with slenderer building component cross-sections, which results in lower component weights. Slenderer cross-sections also reduce the concrete volume and thus transport from factory to building site. Where columns and floors are heavily loaded, higher strength concrete can reduce the cross-section area and thus increase the floor area available to be rented out.