The effect of milled basalt fibers addition on rheological and mechanical properties of alkali activated binder

In this study, the effects of milled basalt fibers addition on rheological behaviour of alkali activated geopolymer binder were determined. This binder was synthesized by alkaline activation of calcined clay stone powder and milled blast furnace slag by potassium silicate solution. Milled basalt fibers as filler were used in range of 0-20 wt% addition to powder part of binder and the effects on rheological and mechanical properties were evaluated. The rheological properties were determined in accordance to flow properties by measurements on Ford viscosity cup and by strain controlled small amplitude oscillatory rheometry measurements of hardening process. The final properties were documented by measurements of flexural strength after 28 days and by scanning electron microscopy. The results indicate that milled basalt fibers addition has effect on flow properties of binder. The flow time increased three times and the complex viscosity is also coherently increased. The reinforcement led to two times higher values of flexural strength and the best figure of merit lied in the range of 1-5 wt% addition of milled basalt fibers.