大温差—紫外耦合作用下聚脲类水工混凝土防护涂层老化规律研究

The western region has a special and complicated climate environment, which is characterized by a large daily temperature difference, intense ultraviolet radiation, severe cold and dry, high wind days and deep covering of permafrost. The construction and service of hydraulic concrete protective coating materials in this area are affected by the climate, which can be easily discolored, pulverized and cracked, and the service life is significantly shorter than that of the mainland. In this study, single factor of indoor accelerated aging, meteorological factors and outdoor natural aging research would be combined, and meteorological factors in the west would be simulated in order to design a large temperature difference-ultraviolet aging double factors coupling indoor test. The adhesion and tear tests of polyurea hydraulic concrete protective coatings would be carried out, the microstructure and morphology of the coating and interface would be analyzed by means of TEM, SEM and IR, the stripping behavior of hydraulic concrete/polyurea protective coating interface would be investigated, and then the microstructure model and the aging attenuation model of polyurea coatings would be established, the aging rule of hydraulic concrete/polyurea protective coating under the coupling effect of large temperature difference-UV would be revealed. This study would provide a theoretical basis for improving the coating weatherability and predicting the service life of hydraulic concrete protective coating materials accurately.

西部地区具有特殊且复杂严苛的气候环境，主要特点为日温差大、紫外辐射强烈、严寒干燥、大风日数多、深覆盖层冻土。该地区水工混凝土防护涂层材料的施工和服役受气候影响，易出现变色、粉化、龟裂等现象，使用寿命与内地相比明显缩短。本项目拟将单因素室内加速老化、气象因子和室外自然老化研究相结合，模拟西部气象因子，设计大温差—紫外室内双因素耦合老化试验。开展聚脲类水工混凝土防护涂层的粘接、撕裂等测试，并利用TEM、SEM、IR等微观表征手段动态分析涂层、界面的微观形貌和结构的变化，考察水工混凝土/聚脲防护涂层界面的剥离行为，建立水工混凝土/聚脲防护涂层界面微结构模型和聚脲涂层老化衰减模型，探讨大温差—紫外条件下的水工混凝土/聚脲防护涂层老化规律。为提高涂层耐候性、更准确地预测水工混凝土防护涂层的使用寿命提供一定的理论依据。

高分子材料在户外使用易出现劣化，尤其在西藏高海拔地区，紫外辐射强烈、日温度波动大、气压低等因素均对高分子类材料的施工和服役存在影响。气象因子难以准确模拟、涂层材料与水工混凝土的界面性能不明、适用西部严苛气候环境的涂层种类有限等原因制约了国内外学者对高寒高海拔地区水工建筑物表面防护涂层材料的研究。. 聚脲弹性体涂层是近年来新研发出的一种新型无溶剂、无污染的绿色材料，具有抗冻融、低温柔性、耐老化、防水抗渗性、耐日照辐射、抗化学侵蚀等优异的物化性能，可以适应高寒地区气候环境。本项目选取了一种综合性能较好的聚脲防护涂层材料，设计了多种模拟西部高寒地区严苛气候条件的室内加速老化试验，包括热空气老化、紫外辐照—冷凝老化、湿热老化、大温差老化、大温差—紫外耦合老化，研究了温度、湿度和紫外辐照对材料性能的影响，揭示了不同老化条件下水工混凝土/聚脲防护涂层界面的老化规律以及聚脲防护涂层材料本体老化规律。. 研究了水工混凝土表面防护涂层在拉萨、厦门、武汉等不同地区气候条件下的室外自然老化情况以及水工混凝土/表面防护涂层界面室外老化规律。坚持长期进行室外老化试验，以便获得更多试验数据，对比老化破坏后界面粘接性能的变化程度，分析室内与室外试验的相关性，以期利用数学方法，设定相关系数并建立公式，构建室内加速老化与室外自然老化试验的换算关系。本项目研究成果为进一步实现材料优选和工艺优化提供了理论依据。