【作者】 鲁彩凤；

【导师】 袁迎曙；

【作者基本信息】 中国矿业大学 ， 结构工程， 2012， 博士

【摘要】 本文将气候环境作用与粉煤灰混凝土微环境响应结合起来，通过建立与混凝土微环境相关的耐久性退化模型（包括碳化深度预计模型、氯盐侵蚀速率预计模型及钢筋锈蚀速率预计模型），从而达到对自然气候环境下粉煤灰混凝土结构耐久性使用寿命进行预计的目的。借助于微观测试仪器，研究了不同龄期下粉煤灰混凝土浆体的微观结构；通过压汞试验法研究了粉煤灰掺量对混凝土孔隙结构的影响程度；通过理论分析及试验验证，研究了粉煤灰掺量对混凝土孔隙液pH值的影响。在恒定人工气候环境下，基于混凝土内部温度响应、相对湿度响应以及相关基本物理量（包括导热系数、湿质扩散系数及孔隙水饱和度）的研究，分析了粉煤灰混凝土微环境温度、相对湿度响应规律；并结合传热过程、传质过程的基本理论，建立了人工气候环境下粉煤灰混凝土微环境温度响应、相对湿度响应预计模型；同时借助自然气候环境温度和相对湿度作用谱，基于粉煤灰混凝土微环境响应预计模型，建立了自然气候环境下粉煤灰混凝土微环境响应的预计方法。基于粉煤灰混凝土中可碳化物质的含量以及CO2在粉煤灰混凝土内扩散速率的研究，从理论上推导了粉煤灰混凝土部分碳化区长度及完全碳化区长度的预测模型，并通过人工气候环境下碳化试验进行验证；建立了自然气候环境下粉煤灰混凝土碳化深度预计方法，并通过现场长期试验加以验证。在人工模拟海洋气候环境下，试验研究了海洋环境条件（包括海洋大气环境、海水环境及海洋潮汐环境）及粉煤灰掺量对氯离子传输速率的影响规律；基于海洋大气环境下氯离子传输机理及试验结果，建立了海洋大气环境下氯离子传输速率预计模型；建立了自然海洋大气环境下粉煤灰混凝土中氯离子侵蚀速率的预计方法，并通过现场长期试验加以验证。通过试验分别确定了碳化、氯盐侵蚀环境下钢筋脱钝的临界条件；基于钢筋不均匀锈蚀分布模型，从理论上推导了自由膨胀阶段钢筋锈蚀量的预计、混凝土保护层锈胀开裂前锈胀力分布模型以及锈胀开裂时钢筋临界锈蚀量预计；基于粉煤灰混凝土内钢筋锈蚀时变模型，建立了自然气候环境下混凝土内钢筋锈蚀速率预计方法，并通过长期试验加以验证。基于上述系列研究成果，分别研究了碳化环境、氯盐侵蚀环境下钢筋脱钝耐久性使用寿命，以及锈胀开裂使用寿命的预计方法，并给出具体算例分析过程。更多还原

【Abstract】 Durability degradation models (including carbonation depth prediction, chloride ionerosion rate prediction, reinforced bar corrosion rate prediction) related tomicro-environment were established by combining natural climate environment withmicro-environment response in fly ash concrete, so as to achieve durability service lifeprediction of fly ash concrete structures in natural climate environment.Microstructure of fly ash concrete cement paste at different ages was studied bymicroscopic instrument; the effect of fly ash replacement on pore structure of fly ashconcrete was researched by mercury intrusion method; the impact of fly ash replacement onpore solution pH value was studied by theoretical analysis and experimental verification.Micro-environment temperature response, micro-environment relative humidityresponse and basic physical quantities (including thermal conductivity, wet mass diffusioncoefficient and pore water saturation) of fly ash concret were tested in artificially controlledclimate environment, to analysis micro-environment response law in fly ash concrete; themodels predicting micro-environment temperature and relative humidity response in fly ashconcrete were created by combining the basic theory of mass transfer process, heat transferprocess with test results; at the same time, with the role of natural climate temperaturespectra and relative humidity spectra, the methods predicting micro-environment response infly ash concrete in natural climate environment were studied.The models predicting full carbonation length and partial carbonation length wereraised based on carbonizable substances contents andCO2diffusion rate in fly ash concrete,and verified by carbonation tests in artificially controlled climate environment; the methodpredicting carbonation depth in fly ash concrete in natural climate environment wasestablished, and verified through on-site long-term test.The effects of ocean environment(including ocean atmospheric environment, seawaterenvironment and ocean tidal environment) and fly ash replacement on chloride ion erosionrate were studied experimentally in artificially simulated ocean environment, and the modelpredicting chloride ion erosion rate in ocean atmospheric environment was set up accordingto chloride ion erosion mechanism in unsaturated concrete and test results; the methodpredicting chloride ion erosion rate in fly ash concrete in natural ocean atmosphericenvironment was established, and verified through on-site long-term test.The critical conditions of reinforced bar depassivation in carbonatinon and chloride ionerosion environment were determined experimentally in artificially controlled climate environment; reinforced bar corrosion at free expansion stage, rust expansion forcedistribution before concrete surface craking were studied theoretically based onnon-uniform reinforced bar corrosion distribution model, as well as rebar critical corrosionwhen concrete surface cracks due to rust expansion; prediction method of reinforced barcorrosion rate in fly ash concrete in natural climate environment was established accordingto reinforced bar corrosion rate time-varying mode, and verified through on-site long-termtest.Based on above research results, durability service life prediction methods of reinforcedbar depassivation in carbonation and chloride ion erosion environment, as well as rustexpansion cracking service life were studied respectively, and specific numerical exampleswere given.更多还原