受压混凝土抗冻耐久性研究

发布时间：2019-01-14 17:28

【摘要】：实际工程中混凝土结构的劣化失效通常是多重破坏因素耦合作用的结果,根据单一因素作用研究分析混凝土结构耐久性问题难以准确反映工程实际。因此,建立模拟真实服役环境-应力状态下的多因素耦合试验方法,研究多因素耦合作用下混凝土结构性能的破坏机理、退化规律及防护措施具有十分重要的意义。本课题主要是针对压荷载与冻融循环耦合作用下混凝土耐久性的问题进行研究的。通过试验研究压荷载和冻融循环间相互耦合作用致使混凝土劣化的过程,并在此基础上对损伤失效过程进行分析并建立相关数学模型。其过程如下： 1.在快速冻融循环条件下进行受压混凝土抗冻耐久性研究时。作者对分别加了0、30%、60%极限压强度荷载的混凝土试件进行快速冻融循环试验,结果发现,加载快速冻融循环条件下的未加载试件比一般快速冻融循环条件下的未加载试件其内部损伤情况要小。 2.在暴露条件下进行受压混凝土抗冻耐久性的研究时。作者对分别加了极限压强度0、30%、60%荷载的混凝土试件进行暴露试验,研究并对比分析了暴露条件下受不同压力混凝土试件内部的损伤变化趋势。结果发现,经过相同时间暴露试验下的混凝土,加载的力越大越有利于其抗压强度的增长,同时在一定范围内又越不利于其抗拉强度的增长。 3.在测试暴露条件下受压混凝土动弹性模量时,提出了失水率的概念,并且建立了以测试时混凝土相对动弹性模量的测试值、失水率及温度为未知量的三元函数修正方程和在一般快速冻融循环试验时不同荷载下混凝土试件相对动弹性模量的修正公式。 4.以哈尔滨市为参考,找出了我国北方寒冷地区暴露于室外的混凝土结构在一个特定时间内共经历的冻融循环次数。
[Abstract]:The deterioration failure of concrete structure in practical engineering is usually the result of the coupling of multiple failure factors. It is difficult to accurately reflect the engineering practice by studying and analyzing the durability of concrete structure based on single factor. Therefore, it is of great significance to establish a multi-factor coupling test method to simulate the real service environment and stress state, and to study the failure mechanism, degradation law and protective measures of concrete structure under multi-factor coupling. The purpose of this paper is to study the durability of concrete under the coupling of compression load and freeze-thaw cycle. The process of concrete deterioration caused by the coupling of compression load and freeze-thaw cycle is studied through experiments. Based on this, the damage failure process is analyzed and the relevant mathematical model is established. The process is as follows: 1. Under the condition of rapid freeze-thaw cycle, the durability of compressive concrete is studied. The authors have carried out rapid freeze-thaw cycle tests on concrete specimens which have been subjected to 60% ultimate compressive load respectively, and the results show that, The internal damage of unloaded specimens under loading rapid freeze-thaw cycles is smaller than that of unloaded specimens under general rapid freeze-thaw cycles. 2. The frost durability of compressive concrete was studied under exposed conditions. The authors carried out exposure tests on concrete specimens with a limit compressive strength of 0 30% and 60% load respectively, and compared and analyzed the internal damage trends of concrete specimens under different pressures under exposure conditions. The results show that the higher the loading force is, the more favorable the compressive strength is to the concrete under the same time exposure test, and the more unfavorable to the increase of the tensile strength in a certain range. 3. When testing dynamic elastic modulus of compressive concrete under exposure condition, the concept of water loss rate is put forward, and the measured value of relative dynamic elastic modulus of concrete in test is established. The modified equation of three-dimension function with unknown water loss rate and temperature and the modified formula of relative dynamic elastic modulus of concrete specimen under different loads under general rapid freeze-thaw cycle test. 4. Taking Harbin as a reference, the freeze-thaw cycles of concrete structures exposed to outdoor in the cold area of northern China were found out in a given time.
【学位授予单位】：哈尔滨工程大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU528

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