短碳纤维局部增强混凝土疲劳性能实验研究

Experimental Study of Fatigue Properties for Partially Short Carbon Fiber Reinforced Concrete

对局部增强短碳纤维混凝土进行三点弯曲疲劳试验,发现相同试件在不同应力水平下的疲劳寿命符合两参数威布尔分布,并由此建立考虑失效概率和高低应力比的局部增强短碳纤维混凝土双对数疲劳方程。在工程应用中可以根据实际情况确定失效概率,运用线性插值得到相应回归系数,求得双对数疲劳方程。通过比较相同应力水平下短碳纤维局部增强试件和素混凝土试件的试验结果,发现仅对混凝土进行低掺量的局部增强就可以成倍地提高混凝土的疲劳寿命。上述结果对混凝土路面工程或一些有特殊要求工程的设计有参考意义。

Three-point bending fatigue tests were carried out for partially short carbon fiber reinforced concrete （PSCFRC） to study its fatigue behaviors. Experimental results show that fatigue life of same specimens at different stress levels is in a good agreement with two-parameter Weibull distribution. Based on above result, a log-log fatigue equation was established by considering PSCFRC failure probability and high/low stress ratio. In engineering application, according to actual conditions, suitable failure probability may be selected, then, regression coefficient may be obtained from linear interpolation. Thus the log-log fatigue equation meeting practical engineering needs is obtained. By comparing the test results between PSCFRC specimens and plain concrete specimens at the same stress level, flexural fatigue life is obviously improved only by enhancing the low-volume of short carbon fiber. Above mentioned results are of important reference significance for concrete pavement construction and some projects with special requirements.