Variation of bending strength of fiber reinforced concrete beams due to fiber distribution and orientation and analysis of microstructure

Abstract

Fiber reinforced concrete is becoming increasingly popular as a construction material, as it can potentially form a ductile concrete. The properties of the fiber reinforced concrete depend on the concrete recipe, the flow of the fresh concrete into the formwork, possible vibrating of the concrete and the fiber orientations. This contribution presents the results of bending tests performed on fiber reinforced concrete beam specimens, which have been cut out of a larger plate. These beams have different fiber orientation distributions, due to being taken from different parts of the plate and with different orientation with respect to the flow of the fresh concrete. Further, the microstructure of the concrete was investigated using scanning electron microscopy (SEM). The SEM shows no obvious differences in the microstructure between beams of different strength and shows good adhesion of fiber and concrete matrix in all investigated samples.