Concrete quality is a key parameter for the durability of structures . The spatial variability of concrete quality also has a significant influence. Degradation caused by chloride induced corrosion or frost induced cracks starts in areas with low resistance of the concrete and severe environmental exposure. Such areas with low resistance are either caused by variations in the quality of the delivered concrete or by insufficient workmanship during casting. Usually, the quality of the delivered concrete is controlled regularly when important structures are cast. However, there is no way to control the quality of the casting process itself, in particular the way a concrete is compacted. It is therefore of great importance that workers with appropriate skills are present on the construction site.