Design equations for steel fibre reinforced recycled aggregate concrete beams based on material and member level testing

![CDATA[This research investigates the feasibility of using optimum value of recycled aggregate concrete (RAC) and steel fibres (SF) in order to provide a sustainable and alternative material to natural aggregate concrete (NAC). New design equations and corresponding safety factors need to be developed when steel fibre reinforced recycled aggregate concrete (SFRRAC) is used in construction, as the existing design provisions are applicable only to NAC. In this research, 25 mixes with varying combinations of recycled aggregate (RA) and steel fibre (SF) contents are investigated. The compressive strength, split-tensile strength and elastic modulus of these mixes are found to increase with SF content and decrease with RA content. Full-scale beam members have been fabricated using the optimum proportions of RA and SF and are yet to be tested for flexural behavior. In this paper, the experimental results of testing another set of SFFRAC beams fabricated previously is discussed. These results show that the flexural moment capacities of SFRRAC beams decrease with RA content and increase with SF content. Based on experimental data, safety factors of design equations for beams are calibrated using the first-order reliability method (FORM) and the reliability index ratios of the nine beams are estimated. The reliability index ratios are found to decrease with RA content and increase with SF content.]]