Metallic vs. Non-Metallic Fibers for UHPC: How to Choose — A Performance Comparison and Selection Strategy Analysis

When selecting fibers for UHPC, how to choose between metallic and non-metallic fibers: performance comparison and selection strategy analysis

In the material system of ultra-high performance concrete (UHPC), fibers serve as the core reinforcing component, and their selection directly affects the mechanical performance, durability, and engineering economics of structures. As an industry leader with 28 years of deep expertise in the UHPC/GRC/GRG/GRP materials field, Qinglong Group draws on its full-chain technical experience to provide designers and owners with scientific fiber selection solutions. This article analyzes the trade-off logic between metallic and non-metallic fibers from three aspects—performance differences, applicable scenarios, and cost control—to help high-end construction projects maximize material value.

1. Metallic Fibers: The "Hardcore Backbone" of Mechanical Performance

Metallic fibers, represented by steel fibers, have become key materials for enhancing the tensile strength and toughness of UHPC thanks to their high strength and high elastic modulus. In practical engineering, micro steel fibers with a diameter of 0.1-0.3mm can push the flexural strength of UHPC beyond 20MPa, while impact toughness is improved by 5-10 times compared with ordinary concrete. The General Technical Conditions for Non-Load-Bearing Components of Ultra-High Performance Concrete (UHPC), developed with participation from Qinglong Group, clearly states that metallic fibers perform outstandingly in heavily loaded structures such as bridges and tunnels, and their electrical and thermal conductivity also makes them suitable for special scenarios such as de-icing pavements. However, note that the rust susceptibility of metallic fibers must be addressed through surface galvanization or stainless steel materials, and they should be selected with caution in highly corrosive environments such as marine engineering.

2. Non-Metallic Fibers: The "Flexible Solution" of Lightweight Durability

Non-metallic fibers such as glass fiber and carbon fiber offer innovative paths toward lightweighting and weather resistance for UHPC. Among them, basalt fiber combines high strength with corrosion resistance. In Qinglong's irregular curtain wall project for the Nanning Convention and Exhibition Center, UHPC panels with 1.5% basalt fiber content achieved a 30% weight reduction compared with traditional metallic fiber solutions, and showed no significant performance degradation after 1000 hours of salt spray testing. Although carbon fiber is relatively costly, a dosage of just 2% can increase the elastic modulus of UHPC by 40%, making it particularly suitable for long-span landscape components. Notably, non-metallic fibers require attention to interface compatibility—Qinglong's R&D center increased fiber-to-matrix bond strength by 25% through silane coupling agent modification technology, effectively addressing the risk of cracking.

3. Selection Decision: Scenario-Oriented Comprehensive Balancing

In practical engineering, fiber selection should follow a three-dimensional evaluation model of "performance-cost-workability." For structural components such as municipal bridges, Qinglong recommends prioritizing copper-plated steel fibers to ensure structural safety for more than 30 years; irregular exterior wall panels for commercial complexes can use glass fiber UHPC, achieving complex curved shapes through Qinglong's proprietary compression molding process. For overseas projects such as a landmark building in Malaysia, Qinglong's team innovatively adopted a hybrid steel-basalt fiber system that both meets local seismic requirements and controls total material costs. In addition, be wary of the hidden risks of low-priced inferior fibers: Qinglong laboratory data show that substandard fibers may cause UHPC components to suffer strength degradation within 5 years.

As a national "Specialized, Refined, Distinctive, and Innovative" enterprise, Qinglong Group has always upheld its mission of "creating beautiful architecture." Through 28 years of accumulated engineering practice, it has formed a full-process solution ranging from material selection to construction and installation. Whether it is the rigid reinforcement of metallic fibers or the flexible adaptation of non-metallic fibers, the final choice must return to the essence of project requirements. Designers and owners are advised to bring material suppliers on board collaboratively at the design proposal stage, and through BIM simulation and performance testing by Qinglong's detailed design team, precisely unleash the value of UHPC materials to jointly create architectural works that combine safety and aesthetics.