Using Steel Meshes for Enhancing Bond Response Between Steel Bars and Steel Fibre Reinforced Recycled Aggregate Self-compacting Concrete

Abstract Centrally pull-out experiments were used to investigate the bond behaviour of steel rods implanted in steel fibre reinforced recycled aggregate self-compacting concrete (SSR). SSR, recycled aggregate concrete (RAC), and natural aggregate concrete (NAC) were all looked into. RCA replacement rates of 0, 30, 50, and 100% were investigated. Pull-out experiments were conducted with 12-mm-diameter ribbed steel rebars. The concrete cover thickness was established at 5.75 at the bar diameter ratio, and the embedding distance of the rebar was set to 10 times the rebar diameter. This work’s main objective is to improve SSR bonding performance by employing a steel mesh fabric (SMF) cylinder. This mesh was positioned concentrically at the same length as the bonding distance of the rebar. The diameters of the conducted SMF cylinders were different (4 and 6 time bar diameter). In addition, SMF was used in two distinct densities. SMF reinforcement ratios were calculated to be 0, 2.33, 3.04, 3.5, and 4.5%. The influence of RCA content, silica fume, steel fibre, and SMF ratio on ultimate bond strength, slip, local bond–slip response, failure mode, ductility, and stiffness of pull-out specimens was investigated. The steel rods implanted in SSR-samples exhibited higher peak ductility and bond strength at RCA = 100%, with maximum growth ratios of 284.7% and 70.2%, respectively, compared to RCA samples that were made of 100% RCA. In addition, when RCA in SSR samples increased, the ultimate slips at peak bond stresses decreased. Ultimate bonding capacity and ductility of steel rods embedded in SSR samples improved by about 45% when SMF ratio reached 4.5%. The bond stiffness decreased as RCA rose, with a falling ratio of 68.5% at 100% RCA. Bond stiffness enhanced as a result of silica fume and steel fibre, with a maximum increase ratio of 181.7% at RCA = 100%. Several models have been presented to predict the ultimate bond strength of RAC and SSR by analysing the effects of concrete type, RCA replacement ratio, concrete cover thickness, bonded length, bar surface qualities, and SMF confinement.