Effects of steel fibers on the flexural behavior of recycled concrete beam: Testing and analysis

Bending tests were conducted on beams made of steel fiber reinforced recycled aggregate concrete (SFRRAC) in this study. The investigation focused on the primary design parameters: watercement ratio, replacement rate of recycled coarse aggregates (RCA), and steel fiber volume fraction. Based on the experimental results of 13 beams in this study and 101 SFRRAC beams from relevant published literatures, the bond coefficients of steel fibers on the recycled aggregate concrete (RAC) beams were calculated using the flexural capacity calculation methods outlined in both Chinese and American specifications for steel fiber reinforced concrete beams. The reliability of the steel fiber bond coefficients was assessed through probabilistic statistical methods, examining their probability distribution. The findings indicate that steel fibers can significantly enhance the flexural behavior of RAC beam. When applying the steel fiber bond coefficient recommended by the Chinese specification for SFRRAC beams, the flexural capacity predictions tended to be non-conservative. Conversely, the steel fiber bond coefficient recommended by American specification led to conservative estimates of flexural capacity. Drawing on the statistical analysis, a reasonable range of steel fiber bond coefficients for SFRRAC beams was proposed, which could better evaluate the flexural capacity of SFRRAC beams while ensuring safety and economy of engineering.