超低温环境下混凝土损伤机理及其防护研究

超低温环境下混凝土主要应用于液化天然气储罐，极地、深海等重要工程领域，其在服役过程中性能退化，威胁重大工程安全。在超低温环境下，受到极端温度环境的影响，导致混凝土损伤因素是多重和交叉的，其组分、结构、荷载等都是引起其损伤的重要原因，但当前相关领域侧重于单因素对其性能变化规律的研究，未见对组分、结构、温度荷载等复杂因素与损伤之间关系的综合评价，没有揭示超低温环境下混凝土损伤的本质原因，更缺乏针对实际应用过程中超低温混凝土防护效果评价方面的研究。因此，本项目拟在常温和普通低温环境下混凝土损伤机理研究的基础上，针对超低温环境下混凝土的研究现状，通过研究其性能劣化规律，明确超低温环境下引起混凝土损伤的因素，揭示损伤机理，建立复杂因素影响下的损伤模型；通过计算机模拟，建立超低温环境下混凝土防护效果评价模型；为降低、防止超低温环境下混凝土的破坏，确保其服役安全提供理论指导与技术支撑。

Concrete in ultra-low temperature environment is mainly used in liquefied natural gas storage tanks，low temperature refrigerated warehouses and important engineering fields such as high cold, polar, deep sea, etc. However, in the course of its service, it causes performance degradation due to damage, which threatens the safety of major projects. In ultra-low temperature environment, affected by extreme temperature environment, the factors leading to concrete damage are multiple and cross-cutting. Its components, structures and loads are all important reasons for its damage. However, the current related research focuses on the study of single factor on its performance change law, and there is no comprehensive evaluation of the relationship between damage and complex factors such as composition, structure, temperature load, freeze-thaw cycle, etc. There is no explanation on the essential causes of concrete damage under ultra-low temperature environment, and also a lack of research on evaluation of protective effect of ultra-low temperature concrete in practical application. Therefore, based on the research of damage mechanism of concrete under normal and ordinary low temperature environment, this project aims at the research status of concrete under ultra-low temperature environment, through studying the law of performance deterioration, clarifies the factors causing concrete damage under ultra-low temperature environment, and reveals the damage mechanism. The damage model of ultra-low temperature concrete under the influence of complex factors is also prefered to be established. The protection effect evaluation model of concrete under ultra-low temperature environment will be established, through computer simulation. Furthermore, it will provide theoretical guidance and technical support for preventing and reducing the damage of concrete in ultra-low temperature environment and ensuring the service safety of concrete in ultra-low temperature environment.