Conception for the repair of historic buildings with architectural concrete façades

The repair of historical concrete structures must aim for the preservation of the original construction and the appearance of the concrete surface. This requires adequate methods which minimize the intervention on the building fabric while guaranteeing the durability and the structural safety. Particularly for repair of architectural concrete, local repair rather than treatment of the entire concrete surface should be carried out whenever feasible on the basis of technological considerations. Such an approach requires a detailed investigation of the structure as well as an estimation of the remaining life time of still undamaged sections of the structure. Suitable repair concretes have to be developed which, in addition to visual similarity with the original concrete, have to satisfy certain requirements with regard to their mechanical properties. In this paper the basis of the methods and procedures for an adequate repair work on historical buildings is presented.