硫酸盐腐蚀与冻融共同作用下井壁混凝土损伤劣化研究

发布时间：2018-04-09 09:16

本文选题：初始损伤　切入点：硫酸盐腐蚀　出处：《煤矿安全》2017年07期

【摘要】：通过试验研究了初始损伤井壁混凝土随硫酸盐腐蚀和冻融循环次数的增加,其质量、超声波传播速度及强度等的变化,运用损伤力学对损伤进行定量评价和参数拟合并借助环境扫描电镜观测分析混凝土微结构的变化。试验结果表明,随着腐蚀和冻融周期循环次数的增加,混凝土的质量呈先增大后迅速减小,超声波传播速度和抗压强度逐渐减小,初始损伤加剧了混凝土性能的劣化;冻融在混凝土损伤劣化中起主导作用,其引起的破坏作用远大于硫酸盐腐蚀。在冻融因素作用下,初始损伤对混凝土性能劣化的影响明显增强;腐蚀和冻融的叠加作用引起混凝土内部微裂纹的产生和连通,而初始损伤的存在使得微裂纹网络体系更加发达,呈现龟裂状延伸和扩展。
[Abstract]:The changes of initial damaged shaft wall concrete with the increase of sulfate corrosion and freeze-thaw cycle times, its quality, ultrasonic propagation speed and strength were studied by experiments.The damage mechanics is used to evaluate the damage quantitatively and the parameters are combined to analyze the change of concrete microstructure with the help of environmental scanning electron microscope.The test results show that with the increase of corrosion and freeze-thaw cycle times, the quality of concrete increases first and then decreases rapidly, the ultrasonic propagation speed and compressive strength decrease gradually, and the initial damage intensifies the deterioration of concrete performance.Freeze-thaw plays a leading role in the damage deterioration of concrete, and the damage effect caused by freeze-thaw is much greater than that caused by sulfate corrosion.Under the action of freeze-thaw factors, the effect of initial damage on the deterioration of concrete performance is obviously enhanced, and the superposition of corrosion and freeze-thaw causes the formation and connectivity of micro-cracks in concrete.The existence of initial damage makes the microcrack network system more developed, showing crack-like extension and expansion.
【作者单位】：北京科技大学土木与资源工程学院;北京建筑大学北京节能减排关键技术协同创新中心;
【基金】：国家重点研发计划资助项目(2016YFC0600800) 国家自然科学基金资助项目(51374036)
【分类号】：TD262

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