Cementitious compositions having highly dispersible polymeric reinforcing fibers

  • US 6,758,897 B2
  • Filed: 12/11/2002
  • Issued: 07/06/2004
  • Est. Priority Date: 04/25/2001
  • Status: Expired due to Term
First Claim
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1. A composition, comprising:

  • a matrix material containing a plurality of individual fiber bodies having an elongated length defined between two opposing ends and comprising at least one synthetic polymer, said individual fiber bodies having surfaces that are substantially free of stress fractures induced by mechanical-flattening of the fiber bodies between opposed rollers, said individual fiber bodies being substantially nonfibrillatable into smaller fiber units after mixing in said matrix material to the extent necessary to achieve substantially uniform dispersal of the fibers therein, and said fiber bodies having a generally quadrilateral cross-sectional profile along said elongated length, thereby having width, thickness, and length dimensionswherein the average width is no less than 1.0 mm;

    wherein the average width is no more than 5.0 mm;

    wherein the average thickness is no less than 0.1 mm;

    wherein the average thickness is no more than 0.3 mm;

    wherein the average length is no less than 20 mm;

    wherein the average length is no more than 100 mm;

    wherein the average fiber width to thickness ratio is no less than 5;

    wherein the average fiber width to thickness ratio is no more than 50;

    wherein said fiber bodies have a Young'"'"'s modulus of elasticity no less than 3 Giga Pascals;

    wherein said fiber bodies have a Young'"'"'s modulus of elasticity no more than 20 Giga Pascals;

    wherein said fiber bodies have a tensile strength no less than 350 Mega Pascals;

    wherein said fiber bodies have a tensile strength of no more than 1200 Mega Pascals;

    wherein said fiber bodies have a minimum load carrying capacity in tension mode no less than 40 Newtons per fiber body;

    wherein said fiber bodies have a minimum load carrying capacity in tension mode no greater than 900 Newtons per fiber body;

    wherein said fiber bodies have an average square area to volume ratio no less than 7.0 mm

    1
    ;

    wherein said fiber bodies have an average square area to volume ratio no more than 22.1 mm

    1
    ;

    wherein said fiber bodies have an average bendability “

    B”

    no less than 20 mN

    1
    *m

    2
    ; and

    wherein said fiber bodies have an average bendability “

    B”

    no more than 1300 mN

    1
    *m

    2
    ;

    said bendability “

    B”

    of said fibers being determined in accordance with the formula, B=1/(3·



    I), wherein the moment of inertia “

    I”

    for a generally quadrilateral cross-section is computed in accordance with the formula, I=1/12·



    t3, wherein “

    w”

    is the average width and “

    t”

    is the average thickness of the generally quadrilateral cross-section.

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