Experimental Research On The Shearing Capacity Of Recycled Concrete Beams Without Stirrups

In this paper, with the contrast tests of 13 recycled aggregate concrete beams without stirrups and natural aggregate concrete beams without stirrups which using concrete with the same axial compressive strength, the effects of shear-span ratio and replacement ratio of recycled coarse aggregate on the characters of shear capacity are investigated. Based on the experimental results, the following conclusions have been drawn:1. The failure modes by shear of recycled aggregate concrete beams without stirrups are similar to the natural aggregate concrete beams without stirrups. Three failure types of recycled aggregate concrete beams are diagonal tension, shear-compression and diagonal compression.2. The stiffness of recycled aggregate concrete beams without stirrups of bending deteriorates is lower than natural aggregate concrete beams without stirrups. The mid-span deflection of recycled aggregate concrete beams without stirrups is bigger than the natural aggregate concrete beams without stirrups in the same loads.3. The cracking strength of inclined section of recycled aggregate concrete beams without stirrups is lower than natural aggregate concrete beams without stirrups. The mean width of diagonal crack of recycled aggregate concrete beams without stirrups is wider than natural aggregate concrete beams without stirrups, with the increasing of replacement ratio of recycled coarse aggregate, mean width of diagonal crack of recycled aggregate concrete beams without stirrups become wider.4. The resisting shear mechanism of recycled aggregate concrete beams withoutstirrups is analyzed, because the minute crack of the recycled aggregate which is generated in the progress of crushing decrease the friction of recycled coarse aggregate, the shear capacity of recycled aggregate concrete beams is a little worse than natural aggregate concrete beams.5. The shear capacity of recycled aggregate concrete beams without stirrups reduceswith increase of shear-span ratio and recycled coarse aggregate. The shear capacity of recycled aggregate concrete beams without stirrups is approximative-ly linear with the replacement ratio of recycled coarse aggregate content. Finally according to test data, a shear capacity formula of recycled concrete beams is proposed and recommended.