Flexural strength enhancement of recycled aggregate concrete beams with steel fibre-reinforced concrete jacket

In this study, the effect of steel fibres reinforced concrete (SFRC) jacketing on the flexural performance of coarse recycled aggregate reinforced concrete (CRARC) beams is studied. A total of 48 reinforced concrete beams, in two categories, were manufactured and tested. In the first category, 16 reinforced concrete (RC) beams were tested, then strengthened with a jacket and tested again. In another category, 16 specimens were strengthened with a jacket and then tested. All specimens were tested using a four-point flexural setup. Coarse recycled aggregate (CRA) was used at two mass replacement ratios, 0% and 100%, in both RC beams and concrete jackets (CJs). Steel fibres (SF) was also added at 0% and 2% (by volume) in both beams and CJs. In these tests, the flexural capacity, maximum displacement at mid-span and the ductility of specimens were measured. Moreover, a new modified model was proposed to predict the flexural behaviour of SF jacketed CRA and coarse natural aggregate (CNA) beams. The obtained outcomes indicate that the maximum flexural strength and displacement of 100% CRARC beams increased substantially by strengthening RC with 2% SF reinforced CJs.