| 摘要: |
| 对经过不同碳化时间的混凝土进行冻融循环试验，测试其力学性能和微观孔隙特征参数，并提出混凝土内部“孔隙曲折度”概念.结果表明：碳化对提高混凝土抗冻性具有恒定的促进作用，碳化3～14d可使混凝土因冻融造成的动弹性模量下降量减少3%～12%；碳化使混凝土内部孔隙曲折度增大；掺加粉煤灰可增大混凝土内部孔隙曲折度，使侵蚀介质的渗透路径变长，进而提高其抗冻性；引气虽然也可提高混凝土抗冻性，但与其内部孔隙曲折度的相关性较低，表明引气和使用矿物掺和料对提高混凝土抗冻性的机理不同. |
| 关键词: 混凝土 冻融循环 碳化 力学性能 孔隙曲折度 |
| DOI：10.3969/j.issn.1007 9629.2017.01.003 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目（51278016） |
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| Influence of Carbonation on Frost Resistance of Concrete and Its Mechanism |
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ZHANG Jinxi, RAN Jin, MA Baocheng, WANG Jiangang
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Beijing Key Laboratory of Transportation Engineering, Beijing University of Technology, Beijing 100124, China
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| Abstract: |
| Rapid freezing thawing tests of concrete were conducted in laboratory after different carbonation times. The mechanical properties and microscopic pore characteristic parameters were investigated， and the concept of “pore sinuosity” of concrete was put forward. The test results indicate that carbonation contributes to enhance frost resistance of concrete， the 314 days carbonation can make dynamic elastic modulus of concrete reduce at least 3%12% due to freezing thawing cycles. Carbonation increases pore sinuosity of concrete. Moreover， fly ash can also enlarge pore sinuosity of concrete， and erosion mediums seepage path becomes longer， thus the frost resistance of concrete is enhanced. The correlation between air entraining and pore sinuosity of concrete is loose， which shows that the mechanism of frost resistance affected by air entraining and mineral admixture for concrete is different. |
| Key words: concrete freezing thawing cycle carbonation mechanical property pore sinuosity |
