Flexural strength in fiber-containing concrete
AssigneeBattelle Development Corporation
InventorDavid R. Lankard
Life of this patent
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Abstract
A method of making a two-phase material comprising a mix of concrete and fibers of a material having a modulus of elasticity of at least about 20 million psi substantially uniformly distributed therein with an average spacing between fibers of up to about 0.3 inch. The flexural strengths are measured for a plurality of substantially different average bond areas of the fibers per unit area in planes normal to tensile stress in test specimens of the two-phase material, and the fibers are provided and distributed in such quantity in the bulk mix that the average bond area of the fibers intersecting planes normal to the stress at known regions of highest tensile stress is sufficient to provide at least a preselected flexural strength in such regions.
Claims9
In a method of making a two-phase material that comprises preparing a concrete mix with fibers of a material having a modulus of elasticity of at least about 20 million psi substantially uniformly distributed therein with an average spacing between fibers of up to about 0.3 inch,
- the improvement of providing the two-phase material with at least a preselected flexural strength by including and distributing the fibers in the mix in the specific quantity that the effective fiber bond area, b, is at least a predetermined value sufficient to provide the preselected flexural strength, and said b is defined as the ratio of the surface area of the fibers intersecting the fracture plane normal to the stress at the known region of highest tensile stress to the area of the fracture plane with both areas expressed in the same units.
Dependencies are inferred from the claim text.