Mechanical performance of concrete combined with a novel high strength organic fiber

• OMP can enhance toughness and residual flexural strength of concrete significantly.
• OMP can substitute steel fiber to improve the anti-seismic performance of concrete.
• An adequate mixing time should be implemented to prevent the uniting of fibers.

A novel organic modified polypropylene fiber (OMP), with a lower specific gravity and greater anti-corrosive property than steel fiber, was used in this study. The mechanical properties of OMP, namely the compressive strength, flexural strength, and flexural toughness, were tested using the four points bending test. The results indicated that, at 7 days, the concrete combined with OMP had a significantly lower compressive strength than the plain concrete, and maintained that status at day 28. The peak value of the concrete’s flexural strength when combined with OMP was lower than that of plain concrete, which corresponded with the compressive strength. The OMP enhanced the toughness, especially the residual flexural strength, of the concrete significantly. As shown in the displacement–load curves, the flexural strength increased with an increase in the OMP added to the concrete. Similarities between the concrete with OMP and concrete with steel fiber were found in the displacement–load curves. Thus, OMP could fully or partially substitute steel fiber in order to improve the anti-seismic performance of concrete while increasing its resistance to corrosion. However, an adequate mixing time should be implemented in order to prevent internal defects caused by the fusion of fibers.