High-Performance Fiber-Reinforced Concrete Mixture Proportions with High Fiber Volume Fractions

An experimental study of high-performance fiber-reinforced concrete (FRC) was performed, showing that high-performance FRC with fiber volume fractions up to 3.75% of 30 mm-long hooked steel fibers can be achieved using conventional mixing and appropriate matrix compositions. Based on this investigation, the optimum fiber content was dependent on mixture design constituents, fiber types, and mixing procedure. Test results showed high-performance steel FRC (SFRC) with 3.75% fiber volume fraction is attainable and can be successfully applied in the field. Fibers were mixable with the mortar and concrete matrices. The mixture was workable and flowable and fiber distribution was uniform. Six mortar mixture proportions, 1 lightweight concrete mixture, and 3 fiber types were tested. Mortar mixtures included cement Types II and V, mortar sand, condensed silica fume, and high-range water-reducing admixtures. Fiber types were hooked steel and straight steel fibers, and polypropylene macrofibers. The mixtures were successfully produced in a ready-mix plant. Flexural strengths obtained varied from 12-24 MPa. Compressive strengths varied from 74-100 MPa and splitting tensile strengths were from 12.6-17 MPa. Flexural toughness of mixtures achieved in this study was 2-3 times higher than those of conventional FRC.