Stress-strain behaviour of steel-fibre-reinforced recycled aggregate concrete under axial tension

The drastic increase in the generation of construction and demolition waste (CDW) is causing serious pollution to the natural environment, such as space reduction, heavy metal contamination, and resource shortage. In this research, steel fibre and recycled coarse aggregate (RCA) are used to form a steel-fibre-reinforced recycled aggregate concrete (SFRAC) to improve the recycling and reuse rate of CDW. Different quality replacement rates of the recycled aggregate (RAR) and volume percentage of the steel fibres (Vf) are used to explore the influence on the tensile behaviour of the concrete. When the Vf increased, the tensile strength and peak strain of SFRAC increased by 10.41–55.90% and 9.70–48.03%, respectively, compared to those of the recycled aggregate concrete (RAC). SFRAC has an energy absorption capacity 5.71–13.31 times higher than that of RAC. The experimental results demonstrate that the internal defects of the RAC on the tensile property can be compensated by the bridging and anchoring effect of the steel fibres. In addition, mathematical formulas are established for predicting the tensile strength, peak strain, and stress-strain curves of the SFRAC. Moreover, SFRAC is recyclable and can be reused at least twice. The method for recycling SFRAC is feasible and cost-effective from an industrial point of view.