Experimental study on the flexural behaviour and ductility ratio of steel fibres coarse recycled aggregate concrete beams

Environmental protection is a fundamental issue in today's world. In this research, the flexural behaviour and ductility ratio of reinforced concrete beams made with steel fibres and coarse recycled aggregate are studied. 27 reinforced concrete beams with a cross-section 150 mm wide, 200 mm high, and a length of 1500 mm, with various transverse reinforcement spacing, were manufactured and tested. Recycled aggregate from building demolition was used at 0%, 50% and 100% mass replacement of natural aggregate. Furthermore, steel fibres were added to improve the flexural behaviour of the beams at 0%, 1% and 2% (in terms of volume). A four-point bending test was performed. In these tests, the flexural capacity, maximum displacement at the mid-span of the specimens and ductility were measured. The effects of the steel fibres and the transverse reinforcement spacing on the flexural behaviour of recycled aggregate concrete beams were the main aims of this study. The results were also compared with ACI, CSA and Eurocode 2 requirements. It was found that the individual effects on the ductility ratio and maximum loading capacity depend on the other parameters (e.g. the steel fibers effect depends on the transverse reinforcement spacing and the effect of the recycled aggregates depends on both the steel fibres content and the transverse reinforcement spacing).