Laboratory Tests of Low-Strength Mortars for Precast Concrete Buildings Designed for Disassembly

Abstract

Direct reuse of precast concrete elements is possible if disassembly is considered in the design phase. An unusual way of designing for disassembly is to use “wet” joints as usual but to optimise the mortar to be less strong and, therefore, easier to remove at the end of the life of the building. A method is presented to test mortars with lime content to determine the shear capacity in the connection between mortar and concrete. Tests are performed with and without an applied normal force and with and without steel bars through the interface. The results show that applying a lime content to the mortar reduces the compressive strength, shear strength and flexural strength. Using steel bars in the connections increases the ductility from less than 1 mm to several mm at the point of failure. The results can be used in future checks of mortar joints in buildings, where it is required to have a minimum strength during the service life and a maximum strength when dismantling. The future mortar requirements will depend on the disassembly method.