Synergistic Enhancement of High-Strength Concrete's Mechanical Strength Through the Utilization of Steel, Synthetic, and Hybrid Fiber Systems

Abstract This investigation addresses the notable gap in understanding the effects of fiber hybridization on concrete performance. The study's primary objective is to enhance the mechanical characteristics of high-strength concrete by incorporating a blend of steel and synthetic fibers. A detailed examination of 192 specimens, categorized into eight distinct groups, was conducted. This analysis focused on the roles of macrosteel and PP fibers in preventing significant cracks and micro-PVA and PP fibers in managing smaller-scale cracking. These specimens underwent stringent testing processes to evaluate the impact of fiber content, limited to a 1% concentration for macrofibers, on the compressive strength (CS) and flexural tensile (FTS) strength of the concrete. The results reveal that integrating steel fibers into concrete mixtures marginally enhances the CS (typically by 4–8%). In contrast, the incorporation of microsynthetic fibers (namely, PVA and PP), was observed to decrease the CS. This finding underscores the complexities inherent in the interaction between fibers and concrete. To support these findings, the study employed advanced nonlinear modeling techniques, concentrating on the interplay between various fiber types and their contributions to concrete strength. The developed models exhibit considerable predictive accuracy. The models showed the significant effect of macro-PP fibers on CS, especially when combined with steel fiber of length 40 mm. This specific blend produces a synergistic effect, notably enhancing the concrete's strength. Overall, this research provides crucial insights into the optimization of fiber-reinforced concrete mixtures, advancing the field by proposing enhanced mechanical performance strategies.