再生保温混凝土在寒冷地区气候条件及荷载共同作用下的耐久性及其长期性能研究

Thermal insulation concrete with recycled coarse aggregate (RATIC) provides an excellent alternative to solve both problems in energy efficiency and the resource recycling in buildings. A study will be carried out to investigate the durability and long-term performances, contributing to accelerate the development of technical standards and application of RATIC in the construction industry. Under the combined action of environment and loads, the combination of durability tests and the numerical analysis will be carried out to access the influence of the characteristics of aggregates on the durability properties of the concrete. The results are of great importance to analyze the quantitative relation between the durability properties and the various factors, such as the components, the compositions of interfacial zones, mechanical parameters, mesostructures and microstructures. The deterioration mechanism will hence be investigated. The medium-term and long-term experiments on the material and the structural members of RATIC will be carried out to evaluate the long-term performances of RATIC. The mechanical property deterioration, failure mode, characteristics and mechanisms of shrinkage deformation, reasons and rules of creep will then be quantified. Meanwhile mesoscopic mechanics and microstructure testing methods will be used to study the mesoscopic and microscopic characteristics of concrete so as to establish numerical analysis model and calculation method. The aggregate shape, gradation, pore gradation and interfacial transition zones are taken into consideration during that process. The long-term performance prediction models of RATIC will be established through the experimental results and theoretical analysis. Then the materials optimization method and durability design principles of RATIC will be provided. These achievements will be valuable for the developing requirements of energy-saving in buildings, construction waste utilization and structure safety.

再生保温混凝土可以实现资源循环再利用，并提高建筑的节能效果。结合标准编制和工程应用，研究该结构混凝土亟需探明的耐久性和长期性能问题。以寒冷地区环境条件为背景，开展荷载与环境因素共同作用下再生保温混凝土耐久性试验，结合数值分析确定再生及保温骨料的骨料特征对再生保温混凝土耐久性的影响规律，揭示再生混凝土耐久性与各相及其界面区的组成、力学参数、细（微）观结构之间的定量关联及劣化机理。长期性能方面，开展再生保温混凝土材料、小型构件中长期试验，确定其力学性能变化及破坏特征、收缩变形特征及机理、徐变成因及规律。同时采用细观力学理论方法和细（微）观测试手段研究其细观特征，建立考虑骨料形状、级配、孔级配及界面过渡区的数值分析模型和计算方法，结合理论分析和试验结果建立功能性再生混凝土的长期性能预测模型。为该混凝土的材料优化与耐久性设计提供理论依据，以适应建筑节能、建筑废物利用与结构一体化的发展需求。

再生保温混凝土实现了结构性混凝土的自保温功能。本项目选择其为研究对象，结合标准编制及工程应用，研究了该材料及构架亟需发展与研究的耐久性和长期性问题。采用宏观试验、细（微）观观测与模拟分析相结合的方法，从宏观和细观材料劣化、长期性能、材料性能提升途径、细观模型建立四个方面展开。主要研究内容及结果：.（1）耐久性方面，考虑了材料使用条件的环境因素，开展了单因素及多因素影响下的耐久性宏观及细（微）观分析。得出了高温、碳化、冻融、侵蚀介质及荷载等因素影响下材料劣化发展规律，确定了材料对于不利自然条件及侵蚀介质、荷载的承受能力，揭示其耐久性与材料组成、原材料性能、细（微）观结构之间的关联及劣化机理。.（2）长期性方面，研究了材料随龄期的强度变化及长龄期的徐变试验研究，比较分析两种骨料（再生粗骨料和保温骨料）的对长期强度和徐变值的影响规律，研究表明由于保温骨料的“内养护效应”对材料的长龄期强度及徐变值均有有利的影响；此外，研究了足尺寸梁构件在短期荷载作用下的抗弯承载力和长期荷载作用下的变形性能，比较分析不同再生粗骨料取代率、保温骨料掺量和钢筋配筋率下的变化规律，研究表明保温骨料的“气弹簧”效应和钢筋配筋率均对梁构件的抗弯承载力和长期变性能有着有利的影响。.（3）采用再生粗骨料强化和外掺玄武岩纤维两种方法来提高再生混凝土的耐久性能和力学性能，通过宏观与细（微）观试验，确定了提升再生粗骨料性能效果最为显著的方法以及提升再生混凝土力学性能的玄武岩纤维体积掺量。.（4）通过数学计算、试验等手段获取混凝土细观模型参数，并建立玻化微珠保温混凝土细观模型，为宏-细观之间的定量关系研究奠定了理论基础。.本项目完成了计划研究内容。研究可以为节能及结构设计优化提供依据，有助于提高节能建筑的安全性、耐久性和节能效果。

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