石灰岩质机制砂混凝土收缩和早期徐变试验研究

发布时间：2018-05-07 04:33

本文选题：石灰岩质机制砂混凝土 + 收缩　；参考：《华中科技大学》2013年硕士论文

【摘要】：随着天然砂资源的减少，机制砂的应用受到了很大的关注，但是国内对机制砂混凝土收缩徐变的研究很少，因此对此类混凝土收缩徐变的研究显得尤为重要。本文主要研究内容如下：比较分析了国内外常用收缩徐变预测模型的考虑因素、适用范围及预测精度，为在实际结构中合理选用预测模型奠定了基础。本文以“石灰岩质集料混凝土及北盘江特大桥长期性能研究”课题为背景，进行了石灰岩质机制砂混凝土的主要材性及配合比试验，并在自然环境下，对石灰岩质机制砂混凝土试验梁进行了收缩、徐变试验，根据实测数据，拟合出机制砂混凝土的收缩应变和徐变挠度系数表达式；并将其与国内外几种常用的收缩、徐变模式：ACI-209、CEB-FIP、GL2000及B3等进行对比分析，结果表明，配筋率对混凝土收缩应变和徐变系数有一定程度的影响。本文还进行了石灰岩质机制砂和普通砂混凝土标准试件的收缩、徐变试验，探讨了不同加载龄期对混凝土徐变系数的影响，并比较了普通砂和机制砂混凝土徐变系数，根据实测数据，拟合出机制砂混凝土的收缩应变和徐变系数表达式，然后对徐变系数表达式进行修正，得到试验梁的徐变应变系数表达式，结果表明，与试验梁徐变挠度系数相比，徐变应变系数大于徐变挠度系数。借助ANSYS和MIDAS/Civil分析软件模拟了混凝土试验梁的徐变，，并将实测结果和模拟结果进行对比分析。
[Abstract]:With the decrease of natural sand resources, great attention has been paid to the application of machine-made sand. However, there are few researches on shrinkage and creep of machine-made sand concrete in China, so it is particularly important to study the shrinkage and creep of such concrete. The main contents of this paper are as follows: The factors, applicable range and prediction accuracy of the commonly used shrinkage and creep prediction models at home and abroad are compared and analyzed, which lays a foundation for the reasonable selection of prediction models in practical structures. In this paper, based on the subject of "study on long-term performance of limestone aggregate concrete and Beipanjiang Bridge", the main material properties and mix ratio tests of limestone mechanism sand concrete are carried out, and in the natural environment, In this paper, shrinkage and creep tests are carried out on limestone machine-made sand concrete test beams. According to the measured data, the expressions of shrinkage strain and creep deflection coefficient of machine-made sand concrete are fitted, and are compared with the shrinkage of several kinds of commonly used concrete at home and abroad. The creep model: ACI-209 CEB-FIPGL2000 and B3 are compared and analyzed. The results show that the reinforcement ratio has a certain effect on the shrinkage strain and creep coefficient of concrete. The shrinkage and creep tests of limestone machined sand and ordinary sand concrete are also carried out in this paper. The effects of different loading ages on creep coefficient of concrete are discussed, and the creep coefficients of ordinary sand and machined sand concrete are compared. According to the measured data, the expressions of shrinkage strain and creep coefficient of machine-made sand concrete are fitted, and then the creep coefficient expression is modified to obtain the creep strain coefficient expression of the test beam. Compared with experimental beam creep deflection coefficient, creep strain coefficient is larger than creep deflection coefficient. The creep of concrete test beam is simulated by ANSYS and MIDAS/Civil software, and the measured and simulated results are compared and analyzed.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU528

【参考文献】