Investigations on composite dowels for lightweight UHPC-elements

Ultra-High Performance Concrete (UHPC) allows the production of extremely thin but high-strength elements. The application of UHPC for concrete walls will reduce the thickness and thus the weight of the walls significantly. Manufacturing of these thin wall-elements will predominantly take place in factories. Consequently, joining techniques for precast UHPC-elements have to be developed in order to connect the thin panels to other structural elements on site. Continuous shear connectors, which are also known as composite dowels, offer the possibility to join these elements by welding. At the Chair of Concrete and Masonry Structures of the Technische Universität München (TUM) a series of Push-Out Tests has been conducted to verify the influence of the panel-thickness, the steel-thickness of the shear connector, the concrete compression strength, the influence of reinforcement and the amount of steel fibers on the shear-bearing capacity and failure mode. The experiments have shown that continuous shear connectors present an excellent connecting method for thin UHPC-panels, if a brittle splitting failure is prevented.