Analysis of Mechanical Performance of Precast Concrete Floor Slabs Containing Recycled Components

The direct utilization of recycled components derived from meticulously demolished old concrete members in new structural elements holds significant potential for saving materials, reducing energy consumption, and lowering carbon emissions. However, the performance of such new members requires systematic investigation for quantitative understanding. As a preliminary exploration, this paper investigated the flexural performance of precast concrete floor slabs containing recycled components. Flexural experiments were conducted under both sagging and hogging moments. The influences of factors such as the surface treatment methods of recycled components and the strength difference between new and old concrete on the sagging moment flexural performance was examined.Furthermore, the effect of the configuration of locally added connecting reinforcement on the hogging moment flexural performance was studied. A calculation methods for the flexural capacity of these slabs was proposed. The results show that: (1) the sagging moment flexural capacity of the recycled-component slabs is significantly higher than that of monolithic cast reference slabs; (2) Different surface treatment methods for the recycled components generally had a limited impact on the sagging moment capacity; (3) the addition of local connecting reinforcement at the ends of the recycled components notably enhanced the hogging moment flexural capacity; for practical engineering, the configuration using directly laid lapped reinforcement is recommended. The results of the proposed methods for calculating flexural bearing capacities are generally conservative.