【摘要】 为了获得具有经济性和良好技术性能的混凝土结构,有必要研究改性腈纶纤维(以下简称腈纶纤维)对混凝土弯曲疲劳强度及疲劳极限的增强作用。用四点加载方法研究了腈纶纤维混凝土梁和底层撒布较长钢纤维的腈纶纤维混凝土梁的弯曲疲劳性能。研究结果表明:当腈纶纤维体积分数为0.085%时,腈纶纤维混凝土梁和底层撒布较长钢纤维的腈纶纤维混凝土梁的弯曲疲劳强度比素混凝土分别提高11.7%和15.7%;当应力水平为0.90时,腈纶纤维混凝土梁和底层撒布较长钢纤维的腈纶纤维混凝土梁弯曲寿命分别是素混凝土的22倍和29.01倍。底层撒布较长钢纤维的腈纶纤维混凝土梁的弯曲疲劳性能优于底层只撒布一层钢纤维或只采用腈纶纤维来增强的混凝土梁。复合纤维增强混凝土适用于道路及机场跑道。更多还原

【Abstract】 The effects of polyacrylonitrile fiber on the fatigue strength and endurance limit of concrete structures were studied using the third-point loading method to determine the fatigue properties of polyacrylonitrile fiber reinforced concrete beams with and without bottom layer steel fibers to design economic concrete structures with excellent properties. The test results show that with a polyacrylonitrile fiber volume fraction of 0.085%, the flexural fatigue strengths of polyacrylonitrile fiber reinforced concrete beam with and without bottom layer steel fibers were larger than the plain concrete beams by 11.7% and 15.7%, respectively. For a fatigue stress ratio of 0.9, the fatigue cycles of the polyacrylonitrile fiber reinforced concrete beams with and without bottom layer steel fibers were 22 and 29.01 times larger than that of the plain concrete beams. The flexural fatigue strength of the polyacrylonitrile fiber reinforced concrete beams with bottom layer steel fibers was better than concrete beams with only bottom layer steel fibers or only concrete reinforced by polyacrylonitrile fiber. The polyacrylonitrile fiber reinforced concrete beam with bottom layer steel fibers is an ideal structure for constructing concrete highway. 更多还原