基于长期暴露试验的海工高性能混凝土耐久性分析

以高耐久性为重要特征的海工高性能混凝土已经在海港码头、沿海和跨海桥梁等基础设施得到广泛的应用。为研究分析海工高性能混凝土在实际海洋环境下长期性能，文章以广东湛江海洋暴露试验站混凝土长期暴露试件为研究对象，在采用传统方法磨粉化学分析氯离子含量分布情况的基础上，采用压汞法(MIP)、背散射电镜(BSE)和能谱分析(EDX)等微观测试技术，测试混凝土的孔结构及水化产物对氯离子的固化性能。经对比分析，海工高性能混凝土比普通混凝土具备更优的孔结构，且长期暴露于氯盐环境下有大量的弗里德尔盐生成，固化氯离子效果显著。长期暴露试验和工程实践证明，海工高性能混凝土是有效提高海洋环境混凝土结构抗氯离子渗透性的根本措施，可显著提高混凝土结构耐久性，大幅延长工程的使用寿命。通过追溯和回顾，陈肇元院士对文章的研究工作给予重要的启发和促进，并对海工高性能混凝土的推广应用发挥重要的推动引领作用。

Analysis on durability of marine HPC based on long-term exposure experiment

Marine high performance concrete (HPC) has been widely used as a highly durable concrete material in marine infrastructures such as wharfs and bridges. To investigate the long-term performance of marine HPC under actual environment, tests were carried out on concrete samples collected from the Guangdong Zhanjiang engineering materials exposure site. Beyond the traditional chloride profile test, the mercury intrusion porosimetry (MIP), the backscattered electrons (BSE) and the energy dispersive X-ray spectroscopy (EDX) were used to characterize the pore distribution and chemical chloride binding of the exposed concretes. The comparison results show that the marine HPC has lower porosity and smaller pore sizes than normal concrete. High amount of Friedel’s salt crystals may be observed in the marine HPC, which reveals significant chloride binding capacity. The long-term exposure experiments and application performance in projects reveal that the marine HPC shall be a basic measure to improve the chloride resistance and prolong the service life for marine concrete structures. In preparing this review of durability research development, Chen Zhaoyuan who had played a great role and made leading contributions to the application of marine HPC provided important inspiration and promotion.