Stress-strain relationship of frost-damaged concrete subjected to fatigue loading
Stress-strain relationship of frost-damaged concrete subjected to fatigue loading
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DOI：
10.1061/(asce)0899-1561(2008)20:1(37
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发表时间：
2008-01-01
影响因子：
3.2
通讯作者：
Sato, Yasuhiko
中科院分区：
文献类型：
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作者：
Hasan, Muttaqin;Ueda, Tamon;Sato, Yasuhiko
本研究试图建立一个模型，用于研究疲劳荷载作用下冻害混凝土压缩时的应力-应变关系。制备混凝土样本并进行冻融循环，然后施加静态和疲劳载荷。仔细测量冻融试验期间以及机械负载试验期间引起的应变。研究发现，随着霜冻作用引起不可逆拉应变的增加，混凝土的静态强度和疲劳寿命会降低。提出了基于冻害引起的初始刚度退化的冻害混凝土在静态和疲劳荷载作用下的应力应变模型。受损混凝土初始刚度的降低根据经验公式为冻融循环引起的剩余膨胀的函数。冻害混凝土在机械静力和疲劳荷载作用下的塑性应变高于原混凝土。因此，受损混凝土的塑性应变不仅是机械荷载下应变水平的函数，而且是霜冻作用引起的不可逆应变的函数。考虑冻害程度的影响，引入卸载和重载刚度因子来解释随着加载循环次数的增加刚度的变化。
This study attempted to develop a model for the stress-strain relationship in compression of frost-damaged concrete subjected to fatigue loading. Concrete specimens were prepared and exposed to freeze-thaw cycles followed by application of static and fatigue loading. The strains induced during the freeze-thaw test were carefully measured as well as during a mechanical loading test. It was found that the static strength and the fatigue life of concrete decreases as increasing irreversible tensile strain was induced by frost action. A stress-strain model for frost-damaged concrete under application of static and fatigue loading based on the degradation of initial stiffness caused by frost damage was presented. The degradation of initial stiffness for damaged concrete was empirically formulated as a function of remaining expansion caused by freeze-thaw cycles. The plastic strain under the application of mechanical static and fatigue loading for frost-damaged concrete is higher than that for original concrete. Therefore, plastic strain for damaged concrete was formulated as not only the function of strain level under mechanical loading, but also the function of irreversible strain caused by frost action. The unloading and reloading stiffness factors were introduced to explain the change of stiffness as increasing the number of loading cycles by considering the effect of the degree of frost damage.