Study On The Behavior Of Reinforced Recycled Aggregate Concrete Beams Under Combined Shear-torsion Action

It is essential and urgent to reuse the scrap concrete comes from the building demolishment or the renovation during the city urbanization. Recycled concrete gives some light to the problem and makes the sustainable development and environment friendly possible compared to the rude landfill. Therefore, it is significant to understand the recycled concrete material properties and expand the material utilization in future.The paper tested the recycled concrete beam under combined action of the shear-torsion stress, the beam loading capacity and mechanical performance are studied with the different torsion shear ratio, stirrup spacing, and coarse aggregate replacement ratio.The paper also self-designed a test set-up, and studied the beam mechanical behavior in torsion, shears and combined torsion-shear forces, in total three working conditions. The beam loading capacity and damaged pattern are concluded from the experimental results, also the effects of different torsion shear ratio, stirrup spacing, and coarse aggregate replacement ratio are analyzed.With the combined loading, the dimensionless correlation between the shear and torsion loading capacity of the recycled concrete beam is obtained, also a semi-experience formula is presented, all based on a variable-angle space truss model. The formula results showed good agreement with the test. Finally, some non-linear simulation of the beam loading capacity under combined action is executed by Abaqus, the simulated results agreed well with the test results.This work is a subtopic of the project "Experiment study and design method to composite mechanical behavior of recycled concrete members and mechanical properties of recycled concrete in the freeze-thaw environment"(Grant No. 51278151), supported by the National Natural Science Foundation.