Bond behaviour of reinforcing bars in self-compacting concrete: experimental determination by using beam tests

Abstract

The force transfer between concrete and reinforcement depends on the bond characteristics between the two materials. Bond influences crack widths and the deflections of RC members and also determines anchorage and splice lengths. Self-compacting concrete (SCC) is characterized by a smaller amount of coarse aggregates when compared to conventional vibrated concrete. To investigate whether this change in mix design has a significant influence on the bond behaviour, a series of beam tests (according to RILEM recommendation RC6) was performed. A total of 36 specimens were cast using 3 different concrete types: one conventional vibrated concrete (CVC) and two powder-type SCC’s. The bond stress—slip behaviour of reinforcing bars with diameters ranging from 12 to 40 mm has been recorded. From these tests, it can be concluded that the bond strength of SCC is even higher than it is for CVC for small bar diameters, but the difference becomes smaller for larger bar diameters.