Steel fibers for concrete come in various sizes and shapes, some bundled and some loose. The types are defined by ASTM A820.
Steel fibers for concrete come in various sizes and shapes, some bundled and some loose. The types are defined by ASTM A820.

Steel fibers as a way to reinforce concrete are not new, but their use has been minimal in the U.S. A recent proprietary study by a reputable industry source has identified the most promising uses as industrial floors and underground structures, including tunnels.

For tunnels, steel fiber-reinforced concrete (SFRC) has reduced liner costs as much as 30%. Not only that, the 3D dispersion of steel fibers is better than the typical 2D reinforcing and could allow a further reduction in temperature and shear reinforcement and also increase the toughness of the surfaces. Steel fibers are not cheap, though, so cost savings are dependent on reduced labor costs.

For high-load floors, typical in manufacturing facilities, steel fibers allow a reduction in the number of joints, which increase the durability of the floors. In some cases, the ideal SFRC includes a mixture of steel and synthetic macrofibers. These so-called “jointless floors” have many applications, including advanced manufacturing and distribution centers that are using robotic equipment.

Steel fibers also have the potential to serve as reinforcement in structural applications. Research at the University of Michigan and support from the Charles Pankow Foundation is being leveraged to push code changes that would allow the use of steel fibers in coupling beams to reduce reinforcement congestion. This application has been successful in at least one west-coast building.

SFRC has great potential with the biggest roadblocks being simply awareness and current building codes that do not recognize the contribution of steel fiber. Some of the most promising growth markets in the United States over the next ten years (such as distribution centers) are also markets with very strong steel fiber potential.