Application of high performance polypropylene fibers in concrete lining of water tunnels

•Adding high performance polypropylene fibers to concrete mix reduced the workability.•Adding fibers to concrete mix decreased the water absorption of concrete by 50%.•HPP fibers had no significant effects on compressive strength.•HPP fibers provided more flexibility and energy absorption capacity than steel fibers.•Adding HPP fibers to the concrete mix reduced chloride ion penetration depth.

In this study, the application of high performance polypropylene fibers (HPP fibers) in concrete lining of water tunnels, was investigated experimentally. A comparison between the behavior of steel fiber reinforced concrete and HPP fiber reinforced concrete with ordinary concrete is drawn. Advantages and shortcomings of HPP fibers used for concrete lining of water tunnels are also presented.The obtained results showed that the HPP fibers were not effective in compressive strength when compared to steel fibers, but the effects of HPP fibers on tensile strength, flexural strength, toughness and energy absorption of concrete were significant. Based on the results, the effects of HPP fibers on concrete characteristics such as the flexural toughness, concrete permeability and resistance to chloride penetration were higher than those of steel fibers. The results also showed that with application of HPP fibers, durability and serviceability of the concrete linings can be improved.