| 摘要 |
Fiber additives for addition to proportioned concrete comprise a plurality of thermoplastic fibers having a profile geometry defined by the equation, wherein the amplitude a0 falls within a range of from about 0.1 df to 2.0 df and the period lambda falls within a range of from about 2 df to 15 df for fibers having a diameter df of from about 0.5 to about 1 mm; the peak pull-out stress sigma peak and the specific pull-out energy absorbed to a maximal displacement of 7.5 mm psi peak, both increase linearly with a deformity factor defined by the equation, where alpha =0.8 and beta =-1, such that the peak pull-out stress is defined by the equation, and the specific pull-out energy is defined by the equation, the fiber additives having an optimimum deformity,Doptimum APPROX (0.5 to 1)Dcritical,Dcritical being that deformity where the ultimate tensile strength of the fiber equals k1 Dcritical+C, and where loads are measured in N; energy in N-mm; length dimensions are in mm, and the values of k1, k2, C and C1 are determined based upon the ultimate tensile strength of the fiber and by plotting deformation versus pull-out stress to obtain the value for Dcritical. The present invention also provides concrete having improved crack resistance and a method for improving the bond slip performance of fibers in concrete utilizing the sinusoidally configured fibers of the present invention. |
