机制砂混凝土抗弯曲疲劳性能研究

摘要

The flexural fatigue performance of manufactured sand concrete(MSC) and river sand concrete (RSC) under constant amplitude of flexural cyclic loading at 5 different stress levels was investigated.The two-parameter Weibull distribution and S-N-Pf flexural fatigue equation were established and analyzed.Furthermore,the Micro-analysis on the interfacial transition zone(ITZ) of MSC and RSC was carried out.The results show that the flexural fatigue lives of MSC and RSC follow the two-parameter Weibull distribution and the distributions of flexural fatigue lives for MSC exhibit lower variability as compared to that of RSC.At the same stress level,MSC exhibits better flexural fatigue performance than RSC and the flexural fatigue lives of MSC are less sensitive to the change of the stress level than that of RSC.The 2 × 106 cycles endurance limit for MSC is calculated to be 55％,which is 2％ higher than that of RSC.The ITZ of MSC has a denser structure and higher micro-hardness than that of RSC.%开展了机制砂混凝土(MSC)与河砂混凝土(RSC)在5种应力水平下的等幅弯曲疲劳试验,进行了混凝土弯曲疲劳寿命的Weibull分布检验,拟合了用于确定等幅荷载下弯曲疲劳寿命的S-N-Pf方程,并对混凝土界面过渡区进行了显微分析.结果表明:MSC和RSC的弯曲疲劳寿命分布均符合两参数Weibull分布,MSC弯曲疲劳寿命离散性整体小于RSC;在相同应力水平下,MSC的抗弯曲疲劳性能优于RSC,且其弯曲疲劳寿命的应力水平变化敏感性小于RSC;弯曲疲劳寿命为2×106次时,MSC的弯曲疲劳强度折减系数为55％,RSC的弯曲疲劳强度折减系数为53％;MSC界面过渡区显微硬度大于RSC,且界面过渡区密实性更好.