膨胀剂对钢管混凝土徐变及其内力重分布的影响

摘要

In order to study the effects of expansive agent dosage on creep performance and force redistribustion of concrete filled steel tube,three creep deformations was tested under 4%,8%,12% expansive agent dosage respectively,and the distribustion regularities were tested for the longitudinal deformation of concrete filled steel tube over time.The test data was calculated for analysis by deformation com-patibility and axil balance equation,and the approximate trends of force redistribution of concrete filled steel tube over time were obtained. The results show that the creep of concrete filled steel tube decrease with the increase of expansive agent dosage,and the force reduction of core concrete is lower when the expansive agent dosage is higher.By pore structure analysis of core concrete,it is discovered that the in-crease of expansive agent dosage make core concrete denser,which make creep deformation and force redistribustion of concrete filled steel tube decrease.%为了研究膨胀剂掺量对钢管混凝土轴压徐变及其内力重分布的影响，进行了膨胀剂掺量分别为4%、8%、12%三种情况下的钢管混凝土徐变变形试验，测试钢管混凝土纵向变形随时间的分布规律。通过变形协调条件和轴向平衡方程，对试验数据进行计算分析，获得不同膨胀剂掺量下钢管混凝土内力重分布随时间变化的大致趋势。研究表明：钢管混凝土徐变随膨胀剂掺量的增加而减小，膨胀剂掺量较高的核心混凝土卸载程度较低。通过核心混凝土气孔结构分析，发现膨胀剂掺量的提高使得核心混凝土变得更加密实，从而减小了钢管混凝土的徐变及其内力重分布。