FATIGUE BEHAVIOR OF NEW ULTRA-HIGH PERFORMANCE CEMENT COMPOSITE

摘要

The paper examines the response of new ultra-high performance cement composite (UHPCC) to static and cyclic loading. The composite is an ultra compact cement matrix with a high volume fraction of metallic fibers. Static and fatigue tests were performed on thin prismatic specimens under flexion. Deflection at mid-span, strain in the constant moment zone and crack opening are monitored using adequate transducers. A critical initial strain threshold is identified; a strong correlation is highlighted between the fatigue life and the initial damage (due to the first static loading). A Woehler curve is rebuilt based on the initial damage measurement (during first static loading) and the characteristic static curve (integrating dispersion). The fatigue endurance limit calculated is equal to 30 MPa, respectively 65 % of the characteristic Modulus of Rupture. A gain of 7% is observed between the bending static behaviour of the specimens being previously loaded in fatigue and those not being loaded in fatigue.