微米级SAP孔设计及对超低温环境中混凝土损伤的抑制机理研究

与传统液化天然气（LNG）储罐相比，“全混凝土”LNG储罐具有储量大、成本低和耐候性强等优点，但LNG储罐内部的超低温环境会诱发混凝土损伤，这制约了“全混凝土”LNG储罐的推广。微米级高吸水性树脂（SAP）孔体系能够吸纳冰体膨胀排出的孔溶液，其优异的稳定性和可设计性使其有望成为抑制超低温环境中混凝土损伤的新技术。本项目拟开展下述研究：①制备微米级SAP，针对混凝土和SAP的特性，形成混凝土中SAP孔体系的设计方法；②通过分析超低温环境中孔溶液的物态变化，解析微米级SAP孔对孔溶液结冰和迁移行为的影响机理；③基于降温过程中混凝土的热变形和开裂行为，阐明微米级SAP孔体系抑制混凝土损伤的机制，形成适于超低温环境的SAP孔体系的调控技术。本研究有助于抑制冰体膨胀造成的混凝土损伤，也可为适于负温环境（0℃至-160℃）混凝土材料的研发提供理论依据和技术支撑。

Compared with traditional liquefied natural gas (LNG) storage tanks, ‘all-concrete’ LNG storage tanks have the advantages of large reserves, low cost, and strong weather resistance. However, the ultra-low temperature in the LNG storage tank will induce the damage of concrete, which restricts the development of ‘all-concrete’ LNG storage tanks. The micron-level superabsorbent polymers (SAP) void system can absorb the pore solution discharged by the expansion of ice. Its excellent stability and designability make it a promising new technology to suppress the damage of concrete at ultra-low temperatures. This research intends to carry out the following aspects: (1) Preparing micron-level SAP and constructing the design method of SAP void system in concrete according to the properties of concrete and SAP. (2) Revealing the mechanism of micron-level SAP void on the icing and migration behavior of pore solution by analyzing the physical state changes of pore solution. (3) Clarifying the mechanism of micron-level SAP void system in inhibiting the damage of concrete based on the thermal deformation and cracking behavior of concrete during freezing, thereby obtaining the regulation strategy of SAP void system suitable for the ultra-low temperatures. This research can help suppress the damage of concrete caused by the expansion of ice and provide a theoretical basis and technical support for designing concrete materials at negative temperatures (0℃ to -160℃).