Resarch On Mechanical Behaviors And Designing Method Of Steel-Reinforced Recycled Concrete Members

The recycled concrete technology is to convert the waste concrete material back into coarse or fine aggregate and to be mixed into the new concrete material. It shares a promising application prospect in the civil engineering field today when lack of resources has become a major issue. Compared with the maturity of the theory system of reinforced concrete structures, recycled reinforced concrete structures ones are in initial stage and rather premature. In this paper, the extended analysis of numerical simulation of mechanical process of slabs, beams, and columns using the ABAQUS software is conducted based on the test results, which conducted by the research team previously, and compares the results to test ones. On this basis, various parameters which could influence on the performance of reinforced concrete beams are studied comprehensively. These parameters are:the replacement ratio, reinforced-steel ratio and thickness to the plane specimens; the replacement ratio, shear-span ratio, stirrup ratio, and reinforced-steel ratio for the beam specimens; the replacement ratio, stirrup ratio, eccentric ratio, slenderness ratio and relative eccentricity for the column specimens. Then, calculation methods, which were given in the codes, are amended and might be adopted in structural design and practical engineering. The conclusion shows:1) As to the slab specimens, the ultimate bearing capacity show a tendency to decrease as the replacement ratio goes up. The growth of stirrup ratio has an obvious contribution to the mechanical performance process and deformation ability of the two-side slab, but shows no tendency to the one-side slab.2) As to the beam specimens, the shear-span ratio has an obvious influence on ultimate bearing capacity, which is, the growth of shear span will sharply decrease the bearing capacity and change the failure mode. The replacement ratio does not significantly affect the bearing capacity, although the decrease of replacement ratio will lead to a trend of the imparity of bearing capacity. Like the normal concrete structures, the increase of stirrup or reinforced steel ratio will be beneficial to the increase of bearing capacity, and when the reinforced-steel ratio reaches a certain level (max ratio), the bearing capacity will reach a plateau.3) As to the column specimens, bearing capacity will slightly increase as the growth of stirrup ratio, or sharply increase as the growth of reinforced-steel ratio, and sharply decrease as the growth of relative eccentricity. In some certain range, the bearing capacity decreases sharply with the growth of slenderness ratio. The influence of stirrup ratio, reinforced-steel ratio and slenderness ratio have tendency to be weakened, as the growth of relative eccentricity.