Flexural behavior of full-scale high-strength recycled aggregate concrete slabs reinforced with steel trusses under one-way repeated loading

To promote the green development of urban buildings constructed with recycled materials, experimental and numerical studies were conducted on the flexural behavior of high-strength recycled aggregate concrete (HSRAC) slabs in this paper. Six full-scale one-way slabs, compromising of four HSRAC slabs and two high-strength natural aggregate concrete (HSNAC) slabs, were tested under one-way repeated loading. Impacts of varied parameters (steel trusses, concrete type, reinforcement ratio and slab thickness) on the flexural behavior were clarified. The test results indicated that arrangement of steel trusses can effectively limit the crack development and enhance the post-cracking stiffness by a maximum of 20 %. The flexural behavior was comprehensively improved including resistance, deformability, stiffness and restoration capacity as the reinforcement ratio increased by 51 %. Thicker slab (150 mm) performed better flexural resisting capacity (over 50 %) and service stiffness (over 70 %) at a cost of ductility loss. HSRAC slabs possessed comparable performance with the HSNAC counterpart, which is a strong affirmation for the promising application of such slabs. Practical finite element (FE) models were then established and verified with test results, and a detailed parametric study was also conducted to provide reference for designing additional important parameters. Finally, a database of 84 bending members was collected and a comparable analysis was carried out to verify the correctness of the tests with a reliability interval of 92 % and enrich the database. Relevant NAC design specifications were evaluated and proved available for safely and accurately predicting the flexural capacity and yield deflection of the proposed slabs, with a deviation range within 15 %.