基于唯象损伤观点的混凝土冻害模型研究

对混凝土冻害机理的认识大多是从材料学角度出发，集中在孔溶液对孔结构的作用上，是从原因学观点出发的物理解释。但鉴于混凝土冻害的复杂性，现在还未统一对混凝土冻害机理的物理认识。从混凝土受冻后宏观性能衰退的表现出发，结合已有的对混凝土冻害在细观上的认识，应用疲劳损伤观点在唯象学层面上理解混凝土冻害的机理是一个新的探索，也为解决现实冻害评估问题提供了定量化手段。本文在综述已有冻害机理的基础上，结合冻融试验及现场检测结果，从细观上分析冻害发展的过程，从宏观材料性能衰退的角度认识混凝土冻害机理，认为混凝土冻害是一个疲劳损伤的过程。最后给出了作者应用疲劳损伤机理建立的混凝土冻害模型，并与已有试验数据比较，验证了模型的合理性。

A study on concrete frost model in view of phenomenological damage theory

Most studies on concrete failure mechanisms by frost are finished by material researchers, those studies try to explain the physical reason how the pore solution acts on the pore structures. Because of the complexity of the cause of concrete failure by frost, there is no accepted theory of concrete frost failure till now. A new phenomenological viewpoint is provided to understand the concrete failure by freeze-thaw cycles. This viewpoint use damage mechanics combined with the meso - understanding of concrete frost process to describe the degradation of concrete properties under freeze-thaw cycles. This viewpoint is also provided a method to estimate the grade of degradation of concrete by freeze - thaw cycle quantitatively. This paper summarizes the available concrete frost mechanism firstly, then analyses some typical experiments of concrete under freeze-thaw cycles and some concrete examination results in situ, gives some meso - analysis of the process of concrete under freeze-thaw cycles, finally concludes that the mechanism of concrete failure by freeze- thaw cycles is fatigue damage. At the end, a fatigue damage model of concrete is provided and compared with available experimental data to prove the validity of fatigue damage mechanism.