高延性纤维混凝土的拉压疲劳试验研究

发布时间：2018-04-03 00:36

本文选题：高延性纤维混凝土　切入点：单轴抗压强度　出处：《西安理工大学》2017年硕士论文

【摘要】：混凝土是目前世界上使用最广泛的建筑材料,其本身具有来源广、造价低、制作简单等优点,因此在当今社会的工程应用中,仍然处于主导地位。然而,传统意义上的四组分混凝土属于脆性材料,变形能力极差,导致结构体在服役期间提前出现劣化现象,降低其工程使用寿命。高延性纤维混凝土是一种基本力学性能和耐久性能良好的新型混凝土材料,它在原有高延性混凝土的基础上增添了纤维组分,成功地提高了混凝土的延展性和韧性。本试验通过大量试验研究了高延性纤维混凝土材料在常温养护下的抗压强度、抗折强度以及抗拉强度,并且参照它的抗拉强度极值,进行了拉压疲劳性能试验研究,分别分析了高延性纤维混凝土材料的基本力学性能和在等幅重复荷载下的疲劳特性。高延性纤维混凝土材料最大的特点就是在受拉时具有拉伸应变-硬化特性和多微裂缝耗能能力。本试验配制的两类轴拉试件均达到了1.4%以上的应变(最大应变可超过4%),强度是普通混凝土的1.6倍左右;高延性纤维混凝土的抗折强度大致是其抗拉强度的4倍左右,远远超过普通混凝土,弯折试验测得的应变值最大可达到4.5%;高延性纤维混凝土具有很高的抗压强度,强度等级相当于C70混凝土,受压时变形能力远超过1%。高延性纤维混凝土在等幅拉压疲劳荷载试验中表现出良好的耐久性能。本次试验共制作了54个试块养护至120d开始试验,观察它在不同应力水平(0.7、0.8、0.9)不同频率(10Hz、20Hz、30Hz)的疲劳荷载作用下的破坏过程以及破环形式,试验结果表明,拉压疲劳荷载下的高延性纤维混凝土疲劳破坏符合威布尔双参数分布,并给出了相应的p-SN方程。本文的研究结果可以为混凝土结构抗震设计、路桥的振动影响等的分析提供了依据,同时可以此作为参照标准评价高延性纤维混凝土材料的抗疲劳能力。
[Abstract]:Concrete is the most widely used building material in the world at present. It has the advantages of wide source, low cost, simple manufacture and so on. Therefore, it is still in the leading position in the engineering application of today's society.However, the traditional four-component concrete is a brittle material, and its deformation capacity is very poor, which leads to the deterioration of the structure in advance during the service period and reduces its engineering service life.High ductile fiber reinforced concrete (HFC) is a new type of concrete material with good basic mechanical properties and durability. It adds fiber component to the original high ductile concrete and improves the ductility and toughness of concrete successfully.In this experiment, the compressive strength, flexural strength and tensile strength of high ductile fiber reinforced concrete under normal temperature curing were studied by a large number of tests.The basic mechanical properties and fatigue properties of high ductile fiber reinforced concrete under constant amplitude repeated load were analyzed.The most important feature of high ductility fiber reinforced concrete is its tensile strain-hardening property and energy dissipation ability of multiple micro-cracks.The two kinds of axial tensile specimens made in this experiment have reached the strain of more than 1.4% (the maximum strain can exceed 4% and the strength is about 1.6 times that of the ordinary concrete, and the flexural strength of the high ductile fiber reinforced concrete is about 4 times of its tensile strength.Far more than ordinary concrete, the maximum value of strain measured by flexural test can reach 4.5.The high ductile fiber reinforced concrete has high compressive strength, its strength grade is equivalent to that of C70 concrete, and the deformation capacity of high ductile fiber concrete is far more than 1 when subjected to compression.High ductile fiber reinforced concrete (HFC) shows good durability in the fatigue test of equal amplitude tension and compression.A total of 54 specimens were made in this experiment for 120 days to start the test. The failure process and the failure form of the specimens were observed under fatigue loads with different stress levels of 0.70.80.9) and with different frequencies (10Hz / 20Hz / 30Hz). The experimental results show that,The fatigue failure of high ductile fiber reinforced concrete under tension and compression fatigue load accords with Weibull double parameter distribution and the corresponding p-SN equation is given.The results of this paper can provide a basis for the analysis of seismic design of concrete structures and the vibration effect of road and bridge, and can be used as a reference standard to evaluate the fatigue resistance of high ductile fiber reinforced concrete materials.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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