寒冷地区海洋环境下混凝土桥梁耐久性研究

发布时间：2018-05-31 05:38

本文选题：寒冷地区海洋环境 + 混凝土桥梁　；参考：《西南交通大学》2017年硕士论文

【摘要】：寒冷地区海洋环境下混凝土桥梁同时受到低温条件和海洋环境的影响,常因耐久性不足提前失效而引发安全问题,造成巨大的经济损失。因此,开展寒冷地区海洋环境下混凝土桥梁耐久性研究,具有重要的理论意义和工程指导意义。本文以曹妃甸工业区青龙河大桥和纳潮河2#大桥为依托,结合工程实际环境,选取影响混凝土桥梁耐久性最主要的冻融循环、碳化作用和氯离子侵蚀作用进行重点研究。通过设计海工高性能混凝土耐久性综合试验,研究不同水胶比、粉煤灰掺量和含气量等因素影响下混凝土抗冻性能、抗碳化性能及抗渗性能变化规律。通过冻融与氯盐盐冻试验,研究了混凝土质量损失率、相对动弹性模量及抗压强度损失率等抗冻性能评价指标在不同影响因素作用下的变化规律,并进行试验对比分析了氯离子对抗冻性能的影响。研究表明氯盐盐冻的质量损失率为抗冻破坏控制指标,对其进行多元线性回归分析,建立了盐冻混凝土质量衰减预测模型,并验证了模型的适用性。通过碳化试验研究了不同因素对混凝土抗碳化性能的影响,分析了碳化深度随时间发展的变化规律,并拟合回归试验结果对经验预测模型进行了验证。通过毛细吸水试验研究了不同因素对混凝土抗渗性能的影响,验证了毛细吸水量与吸水时间的关系,并回归计算得到不同配合比混凝土毛细吸收系数。基于耐久性综合试验研究结果和工程实际,从结构构造设计和施工技术改进两方面,对寒冷地区海洋环境下混凝土桥梁耐久性提升方法进行研究,为今后类似环境下修建混凝土桥梁提供借鉴。
[Abstract]:Under the cold environment, concrete bridges are affected by both low temperature and marine environment, which often lead to safety problems due to insufficient durability and early failure, resulting in huge economic losses. Therefore, it is of great theoretical and engineering significance to study the durability of concrete bridges in the cold marine environment. Based on Qinglong River Bridge and Naochao River Bridge in Caofeidian Industrial Zone, combined with the actual engineering environment, this paper focuses on the selection of freeze-thaw cycle, carbonation and chloride ion erosion, which affect the durability of concrete bridge. Based on the comprehensive test of durability of marine high performance concrete, the changes of frost resistance, carbonation resistance and impermeability of concrete under the influence of different water / binder ratio, fly ash content and air content were studied. Through freeze-thaw test and chloride salt freezing test, the variation law of frost resistance evaluation indexes such as mass loss rate, relative dynamic modulus of elasticity and compressive strength loss rate of concrete under different influence factors were studied. The effects of chloride ions on the frost resistance were compared and analyzed. The study shows that the mass loss rate of chloride salt freezing is the control index of frost resistance. The multivariate linear regression analysis is carried out, and the prediction model of mass attenuation of salt frozen concrete is established, and the applicability of the model is verified. The influence of different factors on the carbonation resistance of concrete is studied by carbonization test. The variation of carbonation depth with time is analyzed and the empirical prediction model is verified by fitting the results of regression test. The effect of different factors on the impermeability of concrete was studied by capillary water absorption test. The relationship between capillary water absorption and water absorption time was verified and the capillary absorption coefficient of concrete with different mix ratio was obtained by regression calculation. Based on the results of comprehensive durability test and engineering practice, the durability lifting method of concrete bridges in cold marine environment is studied from two aspects of structural design and construction technology improvement. It provides reference for the construction of concrete bridge under similar environment in the future.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U448.33

【参考文献】