Facing concrete can be perceived in its complexity only by taking into account the original materials and the entire construction method. Yet, this construction material, concrete, is subjected to varying influences beginning with the composition of its source materials, continuing with processing right up to hardening. Careful planning and vigilant execution of construction work can counteract such influences but they are not always controllable. As a consequence, undesired effects crop up repeatedly. Amongst these are to be found: surface pore holes, marbling, clouding, ridges, misalignments and colouration deviations which can occur over broad areas, locally, in fill layers or as a result of leaking formwork .