摘 要：从硬化水泥石和骨料热膨胀系数的差异出发，根据冻融过程的温度变化，用弹性力学方法计算了温度变化过程中可能产生的温度应力。根据计算结果，提出温度应力是混凝土冻融破坏的一个重要原因。从水的冻结温度与孔径之间的关系以及温度变化对所产生应力的影响两个方面，分析了混凝土冻融试验结果与在实际使用环境中破坏行为的差异。指出冻融试验结果与实际情况之间的关系不仅与孔分布、硬化水泥石和骨料的弹性模量、热膨胀系数有关，还与混凝土配合比有关。因此，提出用相同冻融循环次数时的耐冻温度表征混凝土的抗冻性能比用相同冻融制度时的冻融循环次数更能体现混凝土的组成与结构特征。
Abstract: From the difference of the thermal expansion coefficient between hardened cement paste and aggregate, the temperature stress which may be caused in the process of temperature change is calculated by mechanics of elasticity according to the temperature change in freezing and thawing process. Based on the calculated results, the viewpoint that the temperature stress is the important reason of freezing and thawing destruction of concrete is put forward. From both of the relationship between freezing temperature and pore size and the influence of temperature change on the stress, the difference between the result of freezing and thawing test and failure behavior under in-site working condition is analyzed. It is indicated that the relationship between the result of freezing and thawing test and actual state relates to pore distribution, the elastic modulus and thermal expansion coefficient of hardened cement stone and aggregate, and mix ratio of concrete. Thus, as the characterization of frost-resisting property of concrete, the temperature of cold-resistance under same frequency of freezing and thawing cycle can reflect better the feature of the component and structure of concrete.
Key words: Freeze resistance; Mechanism; Temperature stress; Freezing and thawing temperature
