Steel fibers have been used in concrete for many years. Various bends and hooks have been used to try to increase the bond strength of the fibers to the concrete but none of these configurations was strong enough to allow the fibers to replace reinforcing steel. Helix Micro-Rebar has a polygonal cross section and a twisted (helical) shape that can’t pull out but would have to be twisted out like a screw. These galvanized 1-inch-long pieces increase first crack strength and continue to provide tensile strength after the first crack. Helix claims that by using these tiny rebars a concrete floor on metal deck can be reduced from 4 inches thick to 3 inches. The Helix pieces are added at dosages ranging from 5 pounds/yd3 for crack control up to 66 pounds/yd3 for structural reinforcement. Visit www.helixsteel.com.
