Research On Shear Behavior Of The Reinforced Recycled Aggregate Concrete Beams With BFRP Bars

In order to research on the performances and characteristics of the recycled concrete and the basalt fiber reinforced polymer rebars, and their stress and deformation properties of the recycled concrete reinforced with BFRP rebars, a large number of the relevant literature materials are searched and read for understanding the study situations of the recycled concrete and the BFRP rebars at home and abroad. Then, the shear bearing capacity and the deflection deformation of the recycled concrete reinforced with BFRP rebars are further analyzed by the experimental study.In this paper, 4 recycled concrete beams reinforced with BFRP rebars and 4 recycled concrete beams reinforced with steel rebars are casted and crushed by the two symmetrical concentrated loads at 3 equal diversion point of the test beam span. At the same time, the crack extension and the deflection variation with their corresponding load values are observed,collected and recorded in the process of loading. The influence of the stirrup spacing and the beam section height to the stress and deformation of the 8 test beams are compared and analyzed. And the stress and deformation of the 8 test beams are calculated and analyzed by reference to the current criterion. The conclusions are as follows:(1) Under the same reinforcement condition, the shear bearing capacity of the recycled concrete beams reinforced with BFRP rebars is larger than that of the recycled concrete beams reinforced with steel rebars.(2) Before the test beam cracking, the deflection deformation of the recycled concrete beam reinforced with BFRP rebars is approximate to that of the recycled concrete beam reinforced with steel rebars; but after cracks appear, the deflection of the recycled concrete beams reinforced with BFRP rebars increases significantly faster than that with steel rebars,and the stiffness of the recycled concrete beams reinforced with BFRP rebars reduces more than that of the recycled concrete beams reinforced with steel rebars.(3) In the normal use phase, the deflection deformation of the recycled concrete reinforced with BFRP rebars is larger than that with steel rebars. But after the failure stage,the final deflection deformation of the recycled concrete beams reinforced with BFRP rebars is less than the maximum deflection of the recycled concrete beams reinforced with steel rebars. That is to say, the ductility of the recycled concrete beams reinforced with BFRP rebars is inferior to that of the recycled concrete beams reinforced with steel rebars.(4) With the increase of the section height and the stirrup ratio, the shear bearing capacity of the test beams is increased, and the maximum deflection of the test beams is reduced.(5) The influence of the different stirrup spacing is small to the shear bearing capacity of the recycled concrete beams with the short span.(6) During the normal use phase of the test beams, the calculated deflection values of thecurrent code are consistent with the experimental results of the test beams. However, there are large different between the calculate deflection values of the standards and the experimental values near the failure stage of the test beams.