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类型 基础研究 预答辩日期 2017-11-28
开始(开题)日期 2016-05-18 论文结束日期 2017-09-26
地点 高性能土木工程材料国家重点实验室5300会议室 论文选题来源 国家自然科学基金项目     论文字数 9.30 (万字)
题目 磺化石墨烯改性牺牲混凝土制备、高温性能及与堆芯熔融物相互作用研究
主题词 牺牲混凝土,高温性能,磺化石墨烯,热膨胀模型,堆芯熔融物与混凝土相互作
摘要 核电是一种低碳能源,也是我国未来能源可持续发展的重要基础。牺牲混凝土是欧洲压水反应堆的重要组成部分,该种反应堆是世界上第三代核电技术的代表,该技术的一个重大革新之处在于通过牺牲混凝土的作用,使核电站在严重核事故中对公共与环境安全性更高。 首先,本文探究了不同掺量的磺化石墨烯对牺牲净浆、砂浆的力学性能、高温变形和熔蚀速率的影响。基于该部分研究结果,提出了性能更为优良的石墨烯改性牺牲混凝土配合比。其次,探究了石墨烯改性牺牲混凝土的高温性能,采用新型实验装置,测量了其高温中力学性能。研究了高温作用下石墨烯改性牺牲混凝土热工参数变化规律,并且揭示了高温作用下其热工参数变化机理。采用超声波检测技术,得到不同温度作用下牺牲混凝土试件的超声波波速。根据损伤定义和应力波理论,得到牺牲混凝土损伤与其超声波波速之间的关系,最终建立了不同温度作用下牺牲混凝土的损伤演化模型。再次,开发了高温作用下牺牲混凝土内部蒸汽压力和温度实时测量装置,采用该装置测量了其内部蒸汽压力和温度;基于上述实验结果,根据细观力学构建了一个牺牲混凝土粘弹性热膨胀模型。最后,本文还通过数值建模研究了牺牲混凝土的热工参数(热传导系数、分解焓变)对MCCI过程的影响。本研究工作得到的主要结论如下: 提出了性能更为优良的磺化石墨烯改性牺牲混凝土配合比,在该配合比中磺化石墨烯的掺量选取为0.1% (占胶凝材料的比例)。 采用新型实验设备,探究了牺牲混凝土高温中力学性能。本文研究表明:牺牲混凝土在冷却的过程中存在着损伤恢复,导致高温作用后的强度(抗压强度、劈裂抗拉强度)高于高温作用中的强度,因此材料高温作用后的强度不能真实反映材料在高温作用中的状态。本文得到的牺牲混凝土高温作用中的强度(抗压强度、劈裂抗拉强度),能够更好的指导牺牲混凝土强度(抗压强度、劈裂抗拉强度)设计。 采用Debye理论,揭示了高温作用下牺牲混凝土比热变化的物理机制,本文提出的理论模型预测结果与实验测量得到的比热变化规律一致。根据传热学理论,揭示了高温作用下牺牲混凝土热传导系数、热扩散系数变化机理。在25 ℃~1000 ℃时,牺牲混凝土表现出两种不同的传热机制。在25 ℃~600 ℃时,牺牲混凝土材料主要通过声子传热,而在600 ℃~1000 ℃时,牺牲混凝土材料则主要通过光子传热。 自行设计了蒸汽压力测量管,开发了高温作用下牺牲混凝土内部蒸汽压力和温度实时测量装置。通过该实验装置,可以实时测量在高温作用下牺牲混凝土内部温度分布和蒸汽压力。不同种类的牺牲混凝土的温度和蒸汽压力随时间变化趋势一致,牺牲混凝土内部温度与时间的关联关系可以用二次多项式来表征,而牺牲混凝土内部蒸汽压力与时间的关联关系可以用分段函数来表征。 根据细观力学,构建了一个牺牲混凝土粘弹性热膨胀模型。通过本模型得出的理论结果与实验测量结果比较一致,该模型能够准确的预测牺牲混凝土的高温变形。 采用MELCOR程序,构建了一个严重核电事故情况下的MCCI分析模型,探究了牺牲混凝土的热工参数(热传导系数、分解焓变)对MCCI过程的影响。数值研究结果表明:随着牺牲混凝土热传导系数或者分解焓变的增大,计算得出的牺牲混凝土轴向熔蚀速率均逐渐降低。因此,提高牺牲混凝土的热传导系数或者分解焓变能够延长牺牲混凝土的熔穿时间,从而能够提高反应堆的安全性。
英文题目 PREPARATION AND THERMAL BEHAVIOR OF SACRIFICIAL CONCRETE WITH GRAPHENE SULFONATE NANOSHEETS AND MOLTEN CORE CONCRETE INTERACTION
英文主题词 sacrificial concrete; thermal behaviour; graphene sulfonate nanosheets; thermal expansion model; molten core concrete interaction (MCCI)
英文摘要 Nuclear power is a kind of low-carbon energy, and is also an important foundation for sustainable development of China’s future energy. Sacrificial concrete is a key component of European Pressurized Water Reactor which is the tepical representative of the third generation nuclear technique. The significant innovation of this technique is severe accident mitigation and security improvements of nuclear power plant by utilization of sacrificial concrete. Firstly, the effect of graphene sulfonate nanosheets on mechanical strengths, thermal expansion, and ablation behaviour of sacificial cement paste and mortar was studied, according to the initial mix design of sacrificial concrete. Based on these findings, the mixture of sacrificial concrete containing graphene sulfonate nanosheets was designed. Secondly, the thermal properties of sacrificial concrete with and without graphene sulfonate nanosheets were comprehensively investigated. Two new experimental apparatuses were developed and used to measure mechanical sterngths (compressive strength and splitting tensile strength) of sacrificial concrete during elevated temperatues exposure. Thermal physical parameters (specific heat, thermal conductivtiy, and thermal diffusivity) of sacrificial concrete with and without graphene sulfonate nanosheets were measured, and the variation mecanisms for the thermal physical parameters of sacrificial concrete subjected to elevated temperatures were exposed. Using ultrasonic testing technique, variation of ultrasonic pulse velocity propagation in sacrificial concrete subjected to different high temperatures was detected. According to definition of damage, the relationship between damage of sacrificial concrete and ultrasonic pulse velocity was derived, eventually concluding a correlation between the damage of sacrificial concrete and elevated temperatures that sacrificial concrete subjected to. In addition, the microstructure, porosity, thermal analysis, thermal expansion, ablation behaviour, and damage evolution of sacrificial concrete with and without graphene sulfonate nanosheets before and after exposure to various temperatures were systematically investigated. Thirdly, an experimental setup was designed to measure the real-time temperature and pore vapour pressure of sacrificial concrete during high temperature exposure, and real-time temperature and pore vapour pressure of sacrificial concrete exposure to high temperatures were determined simultaneously. According to those results, a visco-elastic thermal expansion model of sacrificial concrete was established by using a micromechanics approach. Finally, the effects of thermal conductivity and decomposition enthalpy of sacrificial concrete on the process of MCCI were studied throuth numerical simulation. The main conclusions are summarized as follows, The addition of graphene sulfonate nanosheets to sacrificial concrete could improve many properties of the material, and the mixtures of sacrificial concrete containing graphene sulfonate nanosheets were designed in the paper. The optimal amount of graphene sulfonate nanosheets was 0.1wt.% (with respect to weight of binders), considering the mechanical strength, microstructure, and ablation velocity of sacrificial cement paste and mortar. New experimental apparatuses were developed and used to measure mechanical sterngths (compressive strength and splitting tensile strength) of sacrificial concrete during elevated temperatues exposure. The results suggested that the damage induced by high temperature in sacrificial concrete was recoverd slightly during cooling, and the mechanical sterngths (compressive strength and splitting tensile strength) after elevated temperature exposure could not represent the actual situation of sacrificial concrete. Consequently, the mechanical sterngths obtained in the paper could provide a better guidance for strength design of sacrificial concrete. Variation mechanism for specific heat of sacrificial concrete subjected to elevated temperatues was revealed via Debye theory, and the specific heat of sacrificial concrete subjected to elevated temperatures could be accurately predicted by the model established in the work. Variation mechanism for thermal conductivity and thermal diffusivity of sacrificial concrete subjected to high temperatues was exposed by heat transfer theory. In the range of 25 ℃~1000 ℃, there were two different heat transfer mechanisms for sacrificial concrete. During 25 ℃~600 ℃, heat transfer of sacrificial concrete was mainly due to the phonon, while the heat transfer of sacrificial concrete was by means of photon in the range of 600 ℃~1000 ℃. An experimental setup was designed to measure the real-time temperature and pore vapour pressure of sacrificial concrete during high temperature exposure, and real-time temperature and pore vapour pressure of sacrificial concrete exposure to high temperatures were determined simultaneously. The temperature and pore vapour pressure of different sacrificial concretes exposure to high temperatures were consistent, and the temperature-time and pore vapour pressure-time relationships were quadratic polynomial form and piecewise function, respectively. A visco-elastic thermal expansion model of sacrificial concrete was established by using a micromechanics approach. The results of model prediction agreed well with the experimental measurement, which indicated that the thermal expansion of sacrificial concrete under uniform temperature field could be accurately predicted by the model. An MCCI analytical model in severe nuclear accident was set up, and the effects of thermal conductivity and decomposition enthalpy of sacrificial concrete on the process of MCCI were studied throuth numerical simulation. With the increase of thermal conductivity or decomposition enthalpy of sacrificial concrete, the axial ablation rate calculated by the mumerical model was always decreased. Thus, the melt-through time of basemat should be extended, and the safety nuclear power plant could be improved in severe nuclear accident by increasing the thermal conductivity or decomposition enthalpy of sacrificial concrete.
学术讨论
主办单位时间地点报告人报告主题
共青团东南大学委员会、研究生院、党委研工部、科研院 2016年5月14日 纪忠楼Y406 褚洪岩 Thermal properties of sacrificial concrete at high temperatures
东南大学材料科学与工程学院 2017年6月26日 材料A楼601室 Prof. Karen Sciener Investigation on mechanisms controlling hydration kinetics in Portland cement and Portland cement with SCMs
东南大学材料科学与工程学院 2017年4月14日 材料B楼523室 Dr. Venkatesh Kodur Innovative Strategies for Enhancing Fire Performance of Concrete Structures
伦敦大学学院 AIM课题组 2017年5月10日 伦敦大学学院Chadwick 206室 褚洪岩 Thermal properties of sacrificial concrete
东南大学材料科学与工程学院 2016年12月15日 材料A楼601会议室 褚洪岩 Mechanical and thermal properties of sacrificial concrete without and with graphene sulfonate nanosheets at elevated temperatures
东南大学材料科学与工程学院 2015年11月26日 材料A楼601会议室 褚洪岩 Thermal behavior of siliceous and ferro-siliceous sacrificial concrete subjected to elevated temperatures
孙伟课题组 2016年1月30日 材料A楼407室 褚洪岩 2015年终汇报
东南大学材料科学与工程学院 2017年6月24日 材料B楼523室 Prof. Luping Tang Validation of Test Methods and Models for Assessing Durability of Concrete Sturctures
     
学术会议
会议名称时间地点本人报告本人报告题目
中国力学学会、上海交通大学 2015年8月15-18日 上海交通大学(中国、上海) 高温作用下牺牲混凝土的损伤演化
米兰理工大学(Politecnico di Milano) 2016年9月12-14日 米兰理工大学[莱科(Lecco),意大利(Italy)] Mechanical properties and damage evolution of siliceous concrete subjected to elevated temperatures
     
代表作
论文名称
Thermal behavior of siliceous and ferro-siliceous sacrificial concrete subjected to elevated tempera
Mechanical and physicochemical properties of ferro-siliceous concrete subjected to elevated temperat
Mechanical properties and damage evolution of siliceous concrete subjected to elevated temperatures
高温作用下牺牲混凝土的损伤演化
Effects of graphene sulfonate nanosheets on mechanical and thermal properties of sacrificial concret
 
答辩委员会组成信息
姓名职称导师类别工作单位是否主席备注
缪昌文 正高 教授 博导 东南大学
刘加平 正高 教授 博导 东南大学
高玉峰 正高 教授 博导 河海大学
王立彬 正高 教授 硕导 南京林业大学
蒋林华 正高 教授 博导 河海大学
高建明 正高 教授 博导 东南大学
张云升 正高 教授 博导 东南大学
      
答辩秘书信息
姓名职称工作单位备注
佘伟 其他 讲师 东南大学