海工结构用智能纳米碳纤维活性粉末混凝土制备及自监测性能研究

Considering the demand of sensors with high durability, long-term stability and excellent compatibility with marine concrete structures in the process of health monitoring in infrastructures exposed to ocean environment, this project will concentrate on developping carbon nanofibers (CNFs) reactive powder concrete (CNF-RPC) sensor with excellent piezoresistive performance. This project will study the influence of rheology of fresh paste on the dispersion of CNFs in RPC matrix. Based on the CNF-RPC sensor with homogeneity and stable performance, a reasonable scope of rheological parameters and design method of mixing proportion of CNF-RPC will be obtained from this project. Then, the influence of various temperatures, moisture contents, freeze-thaw environment and loading method(including dynamic loading) on the piezoresistivity of CNF-RPC will be determined in the project. The mechanism of the effect on piezoresistivity by environmental factors will be analysed in this task and result revision and signal purification method of self-sensing results in various environment will be achieved from the research. Finally, the self-sensing performance of concrete beam is going to be determined. The CNF-RPC sensors will be embedded in key parts of the concrete beam. Characteristics of static and dynamic response will be determined. The dynamic self-sensing theoretical calculation model will be set up in this study. On the basis of finite element analysis of dynamic self-sensing results, the section of dynamic self-sensing performance for CNF-RPC sensors finite element analyses will be completed and the finite element models will be proposed. Therefore, the researching results will provide theoretical basis and technical support for the performance decay and health monitoring of the marine concrete structure under dynamic load of wind and waves.

面向海工混凝土结构健康监测过程中对传感器高耐久性、稳定性、与混凝土良好相容性的需求，研制压阻性能优良的纳米碳纤维活性粉末混凝土(CNF-RPC)传感器。通过研究纳米碳纤维(CNFs)在RPC中的分散均匀性与浆体流变性的关系，得到适合制备性能均一稳定CNF-RPC的新拌浆体流变参数控制范围和配合比设计方法；通过系统研究多组温湿度、冻融环境和加载方式(包括动荷载)下CNF-RPC的压阻性能，揭示环境因素对CNF-RPC压阻性能的影响机理，建立不同环境下CNF-RPC自感知结果的修正与压阻信号的提纯方法；最后，将CNF-RPC传感器埋入混凝土梁的关键部位，研究CNF-RPC的静、动力响应特征，得出CNF-RPC的自感知动力作用理论模型；基于CNF-RPC动力-电关系的有限元分析，建立动力-电关系的有限元模型。从而为海工混凝土结构受风、浪等动力荷载作用下的性能衰变和健康监测提供理论依据和技术支撑。

本课题面向海工混凝土结构健康监测过程中对传感器高耐久性、稳定性、与混凝土良好相容性的需求，研制压阻性能优良的活性粉末混凝土材料。通过研究导电纤维材料(纳米碳纤维和不锈钢纤维)智能RPC中的分散均匀性与浆体流变性的关系，得到适合制备性能均一稳定智能RPC的新拌浆体流变参数控制范围和配合比设计方法；通过系统研究多组温湿度、冻融环境和加载方式(包括动荷载)下智能RPC的压阻性能，揭示环境因素对智能RPC压阻性能的影响机理，建立不同环境下智能RPC自感知结果的修正与压阻信号的提纯方法；最后，将智能RPC传感器埋入混凝土梁的关键部位，研究智能RPC的静、动力响应特征，得出智能RPC的自感知动力作用理论模型；基于智能RPC动力-电关系的有限元分析，建立动力-电关系的有限元模型。从而为海工混凝土结构受风、浪等动力荷载作用下的性能衰变和健康监测提供理论依据和技术支撑。