Experimental Investigation of Connections for Reuse of Hollow Core Slabs

The reuse of structural concrete elements may be an important part of lowering CO2 emissions and the use of natural resources in the building industry. In Denmark and other countries, many buildings from the 1960’ies and 1970’ies will be demolished or refurbished in the coming years. Many of these buildings are constructed as precast concrete element buildings. Hence, there exists an enormous potential for reusing these concrete elements in new buildings. This paper experimentally investigates how hollow core slabs can be directly reused. The experimental investigation focuses on a new design for the wall-slab connection. The design of this connection can be used both for the reuse of hollow core slabs and for new slabs. Furthermore, the connection is designed for disassembly, which means that the slabs can be disassembled and reused again.
The experimental investigation concerns a large experimental programme, that
consists of both slabs from an old building and newly produced hollow core slabs. The old slabs come from one of the Danish demolition projects and serve as evidence of the conditions and how the strength of reused slabs can be found. The new slabs ensure that relevant design parameters are varied to establish experimental evidence. The experimental evidence includes the ultimate capacity and failure mechanisms. The failure mechanisms are studied with photogrammetry to monitor crack development and crack kinematics. The experimental evidence suggests that the new type of connection can be used for reused hollow core slabs with transverse reinforcement. For newer hollow core slabs without transverse reinforcement, this type of connection is sensible to concentrated loading and may result in brittle failure modes.