| 摘要 |
<p>Fiber additives for addition to proportioned concrete comprise a plurality of thermoplastic fibers having a profile geometry defined by equation (I), wherein the amplitude a0 falls within a range of from about 0.1 df to 2.0 df and the period μ 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 σpeak and the specific pull-out energy absorbed to a maximal displacement of 7.5 mm γpeak, both increase linearly with a deformity factor defined by equation (II), where α = 0.8 and β = -1, such that the peak pull-out stress is defined by equation (III), and the specific pull-out energy is defined by equation (IV), the fiber additives having an optimum deformity Doptimum ≈ (0.5 to 1)D¿critical, Dcritical? being that deformity where the ultimate tensile strength of the fiber equals k1 D¿critical? + 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 D¿critical?. 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.</p> |
