Durability performance of hybrid reinforced concretes (steel fiber + polyolefin fiber) in a harsh marine tidal zone of Persian Gulf

•Fibers bridge between cracks and prevent propagation of cracks.•Steel fibers increase the risk of corrosion while polyolefin fibers reduce it.•Polyolefin fibers are more effective than steel fibers in improving flexural strength.•Fibers have not considerable effects on compressive strength. Adding fibers into concrete mixture has been an attractive subject for researchers to determine how various forms of fibers change the performance of concrete. This paper reports the findings of a study on the impact of using steel fibers and polyolefin fibers at three volume ratios on the long-term performance of concrete when subjected to a high chloride medium. The concrete properties that were measured include compressive strength, flexural strength, water permeability under pressure, electrical resistivity, half-cell test, and water absorption. Results showed that fibers have no considerable impact on compressive strength while they can improve the flexural strength by up to 28%. Electrical resistivity and half-cell test results showed that polyolefin fibers improve the concrete performance against corrosion while steel fibers reduce the corrosion resistance of concrete. Moreover, steel fibers in hybrid mixtures attenuate the positive impact of polyolefin fibers on the corrosion performance of concrete.