Abstract

The researches on micromechanical properties of concrete subjected to freeze-thaw cycles are few. Under freeze-thaw action, the changes of micromechanical structure and mechanical properties of mortar and interfacial transition zone (ITZ) were characterized by nanoscratch. The volume fraction of micropores increases almost linearly, up to approximate 45%. Moreover, the scratch hardness of different micro-phases in mortar and ITZ decreases gradually with the increase of freeze-thaw cycles, which can be attributed to the increase of micropores. In addition, the thickness of the ITZ gradually increases to 60 um under 1500 F-T cycles, which is consistent with the results using SEM.

中文翻译：

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冻融条件下混凝土的微机械性能

摘要

冻融循环后混凝土的微机械性能研究很少。在冻融作用下，砂浆和界面过渡区（ITZ）的微观力学结构和力学性能的变化以纳米划痕为特征。微孔的体积分数几乎呈线性增加，达到大约45％。而且，随着冻融循环次数的增加，砂浆和ITZ中不同微相的抗划伤硬度逐渐降低，这可以归因于微孔的增加。另外，在1500 FT循环下，ITZ的厚度逐渐增加到60 um，这与使用SEM的结果一致。