Structural behaviour of powder-type self-compacting concrete: Bond performance and shear capacity

An experimental test program was carried out to investigate the bond and shear performance of powder-type self-compacting concrete (SCC). In order to examine the bond strength of reinforcement in concrete, pull-out tests (according to RILEM recommendation RC6 part 2) were performed. In total, 72 pull-out specimens were tested, cast with different concrete mixtures and rebar diameters (8, 12, 16, and 20 mm). It was found that SCC shows normalized characteristic bond strength values as high as or higher than vibrated concrete (VC). In addition, as the bar diameter increases, larger bond strengths are measured, with the highest values for bars with diameter 12 or 16 mm. When larger diameters up to 20 mm are used, a decrease in bond performance is noticed. To study the shear behaviour, four-point bending tests were executed. Small SCC and VC beams were cast with different reinforcement ratios (1.0%, 1.5%, and 2.0%) and tested with different shear span-to-depth ratios (from 1.5 to 3.0), with a total of 102 beams. A slightly decreased shear capacity is observed for SCC. Also, higher ultimate shear stresses are recorded when higher reinforcement ratios or smaller shear span-to-depth ratios are applied.