TY  - EJOU
AU  - Feng, Qi 
AU  - Hu, Weijie 
AU  - Liu, Lu 
AU  - Luo, Junhui 

TI  - State-of-Art on Workability and Strength of Ultra-High-Performance Fiber-Reinforced Concrete: Influence of Fiber Geometry, Material Type, and Hybridization
T2  - Structural Durability \& Health Monitoring

PY  - 2025
VL  - 19
IS  - 6
SN  - 1930-2991

AB  - Ultra-high performance fiber-reinforced concrete (UHPFRC) has received extensive attention from scholars and engineers due to its excellent mechanical properties and durability. However, there is a mutually restrictive relationship between the workability and mechanical properties of UHPFRC. Specifically, the addition of fibers will affect the workability of fresh UHPFRC, and the workability of fresh UHPFRC will also affect the dispersion and arrangement of fibers, thus significantly influencing the mechanical properties of hardened UHPFRC. This paper first analyzes the research status of UHPFRC and the relationship between its workability and mechanical properties. Subsequently, it outlines the test methods and indicators of UHPFRC workability, including fluidity, slump, V-funnel passing time, and rheology. Then, it reviews the impacts of metal fibers, synthetic fibers, hybrid fibers, and other fibers on the workability and mechanical properties of UHPFRC, and presents a reasonable range of fiber dosage for workability and mechanical properties. Key findings include: (1) Steel fibers within 1%–2% volume optimize workability-mechanical balance, while exceeding 2.5% reduces compressive strength by 7%–30%; (2) Hybrid steel-polypropylene fibers enhance toughness by 65%; (3) Fiber orientation control via rheology-modifying admixtures improves flexural strength by up to 64%. This review establishes a fiber factor (V·L/D) for predictive mix design, advancing beyond empirical approaches in prior studies.
KW  - UHPFRC; steel fiber; workability; mechanical properties; synthetic fiber

DO  - 10.32604/sdhm.2025.072955