An investigation on the mechanical, durability and microstructure properties of fiber reinforced self-compacting concrete with mineral powders

Mechanical, durability and microstructure properties of fiber reinforced self-compacting concrete (FRSCC) were investigated in the scope of this study. Flexural and compressive performance were determined as mechanical properties. Microstructural analyses were performed on the specimens that were exposed to the freeze ? thaw (F-T) effect. The effects of fifty percent (wt.) ground granulated blast furnace slag replacement, two different types of steel fiber (macro and micro) and air entraining admixture on mechanical performance and F-T durability were studied. Dosage of steel fiber was forty kilograms per cubic meter and hybrid usage of macro and micro fibers were also studied. Fresh state test results showed that GGBFS has an improvement effect on rheological properties. Steel fibers affected fresh state performance adversely and this negative effect gets more important with an increasing of fiber aspect ratio. Steel fiber usage generally improved mechanical properties. GGBFS replacement exhibited better mechanical performance than only cement binder usage at later ages. Steel micro fibred self-compacting concrete exhibited deflection softening but macro fiber usage caused deflection hardening behavior under flexural loading. Morever steel fibers changed fracture behavior of plain concrete completely and fracture energy values of FRSCC were from twenty to ninety times of plain self-compacting concrete (SCC) specimens. The best performance from the point of fracture nergy was exhibited by macro fiber usage. All SCC and FRSCC series showed satisfactory F-T resistance. High amount of GGBFS as an industrial by-product can be used in SCC without important mechanical loss due to F-T cycles.