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Steel fibers and their aspect ratios are important parameters that have significant influence on the mechanical properties of ultrahigh-performance fiber-reinforced concrete (UHPFRC). Steel fiber dosage also significantly contributes to the initial manufacturing cost of UHPFRC. This study presents a comprehensive literature review of the effects of steel fiber percentages and aspect ratios on the setting time, workability, and mechanical properties of UHPFRC. It was evident that (1) an increase in steel fiber dosage and aspect ratio negatively impacted workability, owing to the interlocking between fibers; (2) compressive strength was positively influenced by the steel fiber dosage and aspect ratio; and (3) a faster loading rate significantly improved the mechanical properties. There were also some shortcomings in the measurement method for setting time. Lastly, this research highlights current issues for future research. The findings of the study are useful for practicing engineers to understand the distinctive characteristics of UHPFRC.

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The structural behavior of RC beams subjected to non-uniform steel bar corrosion is studied here by developing a simplified numerical approach. At first, a modeling methodology for the steel bar corrosion is presented. Then, 3D nonlinear finite element analysis is carried out to assess the residual structural performance of RC beams with non-uniform steel bar corrosion. Obtained results from the numerical study were verified with the experimental work. Six reinforced concrete beams with identical dimensions and reinforcement layout were tested under static loading. Out of the six beams, five beams were subjected to a different level of corrosion using an electrochemical method, and another beam was used as a control specimen without corrosion. Results from the experimental and numerical study demonstrated that nonuniform corrosion of steel bars led to a significant decrease in the load carrying capacity and ductility of the RC beams. Findings of this study will be useful in assessing the residual structural performance of the RC structures with non-uniform steel bar corrosion.

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