南京航空航天大学硕士学位论文基于温度应力试验机试验的混凝土早期抗裂性研究姓名：董波申请学位级别：硕士专业：结构工程指导教师：高培伟20080101南京航空航天大学硕士学位论文 i 摘 要 混凝土早期由于自身水化等因素产生膨胀或收缩，变形受到约束时，便产生约束内应力，而混凝土早期强度低，内应力超过混凝土抗拉强度便产生微裂缝，这种承载前的裂缝对结构的耐久性产生极坏的影响。影响混凝土早期开裂的因素多，并且错综复杂，因此迫切需要能将混凝土性能量化的试验方法和综合的评价指标，优化混凝土配比设计，以提高混凝土的抗裂性。 本文在研究国内外温度应力试验机的基础上，改进温度应力试验机在混凝土开裂试验方面的性能，通过多组单项性能调试试验和四组完整的混凝土开裂试验，改善了温度应力试验机温度、位移以及应力测试和控制方面的性能，成功地实现了水循环控制混凝土环境温度，并能使混凝土试件的温度较好的模拟实际工程中的温度历程。 本文利用大型有限元分析软件 ANSYS 进行混凝土早期温度应力场的计算， 计算结果与温度应力试验机试验结合，优化混凝土抗裂性的评价和研究体系。为了验证模型建立的合理性，本文将绝热状态下的有限元温度场结果与文献中的经典结论对照，对比了模型绝热温升与试验绝热温升数据；分析了温度应力试验机试件不同位置应力随时间变化的规律，验证了夹头部位的应力集中现象。 最后，总结了本文存在的问题和需进一步开展的工作，为混凝土早期开裂评价体系的建立和温度应力试验机试验方法标准化提供了参考。 关键词关键词：混凝土，温度应力试验机，有限元，早期开裂，温度应力场 南京航空航天大学硕士学位论文 iii Abstract Bases on the hydration of the concrete, the shrinkage or the expand comes into being at early age. If the shrinkage (or the expand) was restricted, internal stresses would be occurred in the concrete. And the concrete would crack at the time of the internal stress bigger than the tensile strength. This kind of non-structural crack does great harm for the durability of concrete. Factors which lead to the crack of concrete are various and most of them are act or react on each other. So in order to get the most appropriate concrete which has batter cracking resistance, The testing method which can quantify the property of concrete and the aggregative indicator which can evaluate the cracking resistance of concrete are important and necessary objects to study. Based on the study of the temperature-stress testing machine allover the world, this paper improved the equipment to make the results tested by TSTM more accurate. Teams of test which study the individual performance and four groups of integrate concrete cracking test have been put up, to improved temperature, displacement and stress testing and performance control of the temperature stress testing machine. Success in achieving the water cycle control temperature of concrete and concrete specimens can better simulate actual engineering course of the temperature of different parts. In order to verify the reasonableness of the model, the paper compared finite element results under adiabatic temperature field with the classic Conclusion: compared the adiabatic temperature rise of the experiment with the model adiabatic temperature data; analysis the development of stress in different place of temperature-stress testing machine, which can explain the stress concentration at the fixed collet. Finally, the existing shortages in this paper were indicated and the research direction in the future was put forward. The content and conclusions of this paper 基于温度应力试验机试验的混凝土早期抗裂性研究 iv may provide a reference for evaluative system of cracking resistance of early age concrete, also for the standardization of the test of temperature-stress testing machine. Key Words: concrete, temperature-stress testing machine, cracking resistance indicators, finite element, early age cracking 南京航空航天大学硕士学位论文 vii 图表清单 图 1.1 不同抗裂指标对同一系列混凝土抗裂性评价比较. 6 图 1.2 单轴约束开裂试验架装置图. 8 图 1.3 Springenschmid 研制的 TSTM 装置示意图 . 10 图 1.4 双试件 TSTM 试验示意图 . 10 图 1.5 最新 TSTM 实物图 .11 图 1.7 清华大学闭环测试系统 TSTM 实物图 .11 图 2.1 温控箱水循环路径示意图. 20 图 2.2 改进前上水板结霜情况. 20 图 2.3 改进后上水板结霜情况. 21 图 2.4 四水板温度均匀性曲线. 22 图 2.5 试件温度测点布置示意图. 23 图 2.6 两夹头处温度与试件中心温度对比曲线. 24 图 2.7 水板均值温度、水箱温度及试件温度对比曲线. 25 图 2.8 模拟 19.2h 温度曲线试验情况. 26 图 2.9 前 5h 水槽温度与试件温度发展情况. 27 图 2. 10 19.2h 水槽温度与试件温度发展情况. 27 图 2.11 模拟 48h 温度曲线试验情况. 28 图 2.12 机械部分改进前试件断裂部位照片. 30 图 2.13 试件结构尺寸示意图. 31 图 2.14 位移测量基准铟钢棒布置照片 . 32 图 2.15 机械部分改进后试件断裂部位照片. 32 图 2.16 3033h 两 LDVT 测得微应变