ABSTRACT
Joining of old and new concretes becomes necessary in the restoration of damaged or partially damaged elements; fabrication of parts of concrete and reinforced concrete structures of large dimensions; grouting of prefabricated reinforced concrete elements; and enlargement of the size of existing concrete and reinforced concrete structures. The reliability of the joint between old and new concrete depends on the surface preparation of old concrete, gluing ability and thickness of the adhesive layer, properties of new concrete, sequence of implementation of individual operations etc. This chapter discusses the experimental studies conducted on a series of control specimens to select suitable compositions for creating a solid bond between old and new concretes. It can be concluded that thin layers of polymeric adhesives in the contact zone of concrete joints help in restricting the absolute deformations of joints to small magnitudes; and enhanced deformability of the boundary layers should be taken into consideration under certain conditions of service of the structure.
