RockStaples® are an enhancement to the concept of white fiberglass “fiber create” used for some years now. Most common concretes are brittle and crack during the curing process which is normal. Concrete just cracks easily in tension; this is why rebar and mesh are placed within the concrete. Under load, the concrete takes the compressive forces and the mesh and rebar the tensile loads with both working as a system to carry shear forces. Think of RockStaples® as a refined form of tiny basalt rebar with high tensile strength and excellent adhesion that ties the cement, sand, and aggregate together at a micro level to further reduce cracking.
RockStaples™® have a density balance with concrete so they do not float and they do not sink. RockStaples® do not “clump” like fiberglass. Like the aggregate itself, RockStaples® uniformly distribute within cement paste during mixing. As a load is applied, concrete containing RockStaples® distributes the stress throughout the concrete in all directions. As Portland based concrete inevitably shrinks and cracks during the curing phase RockStaples® significantly reduce the size of the cracks. RockStaples® “staple” the concrete components together thereby raising the flexural tensile strength.
The strength enhancement RockStaples® add is purely that of the number of fibers crossing the various shrinkage stress points, more fibers = higher strength. We recommend minimum dosages of 10 pounds per cubic yard for crack control and increasing residual strength after cracking by about 3 Mpa. In cases where rebar and mesh are not possible, we have seen great success with dosages to 160 pounds per cubic yard resulting in about a 15 Mpa improvement in residual strength after cracking.