本研究调查了实验室大坝混凝土在不同养护环境下的10年长期服役性能以及17年龄期实验室混凝土和三峡大坝实际钻取混凝土芯样的微观结构。随着时间的推移，无论是自然环境养护还是标准环境养护，实验室大坝混凝土的力学性能都在不断提高。此外，实验室大坝混凝土在17年后仍表现出良好的抗侵蚀性能和致密的微观结构。但在当地自然环境中养护和长期暴露后，抗冻性会降低。实验室混凝土样品的微观结构分析表明，中热水泥和细粉煤灰（FA）颗粒几乎完全水化，形成了由大量水化硅（铝）酸钙[C-(A)-S-H]凝胶和少量晶体组成的致密微观结构。由于长期的火山灰反应，在微观结构中未观察到明显的界面过渡区。这种致密且均匀的微观结构是大坝混凝土具有优异长期服役性能的关键原因。高粉煤灰含量对后期大坝混凝土的微观结构致密化和性能提升也起到重要作用。但从大坝表面区域钻取的混凝土的微观结构疏松、孔隙率较高，这表明直接暴露在实际服役环境中的混凝土因受到水和风的侵蚀而劣化。在本研究中，宏观性能和微观结构分析均表明，中热水泥和粉煤灰的应用最终会形成致密、均匀的微观结构，从而确保三峡大坝混凝土在17年后仍具有优异的长期服役性能。长期暴露于实际服役环境可能会导致混凝土表面的微观结构劣化。因此，需要对留存的长龄期大坝混凝土样品进行深入研究，以便更好地了解其微观结构的演变和性能发展。

This study investigates the long-term performance of laboratory dam concrete in different curing environments over ten years and the microstructure of 17-year-old laboratory concrete and actual concrete cores drilled from the Three Gorges Dam. The mechanical properties of the laboratory dam concrete, whether cured in natural or standard environments, continued to improve over time. Furthermore, the laboratory dam concrete exhibited good resistance to diffusion and a refined microstructure after 17 years. However, curing and long-term exposure to the local natural environment reduced the frost resistance. Microstructural analyses of the laboratory concrete samples demonstrated that moderate-heat cement and fine fly ash (FA) particles were almost fully hydrated to form compact microstructures consisting of large quantities of homogeneous calcium (alumino)silicate hydrate (C-(A)-S-H) gels and a few crystals. No obvious interfacial transition zones were observed in the microstructure owing to the long-term pozzolanic reaction. This dense and homogenous microstructure was the crucial reason for the excellent long-term performance of the dam concrete. A high FA volume also played a significant role in the microstructural densification and performance growth of dam concrete at a later age. The concrete drilled from the dam surface exhibited a loose microstructure with higher microporosity, indicating that concrete directly exposed to the actual service environment suffered degradation caused by water and wind attacks. In this study, both macro-performance and microstructural analyses revealed that the application of moderate-heat cement and FA resulted in a dense and homogenous microstructure, which ensured the excellent long-term performance of concrete from the Three Gorges Dam after 17 years. Long-term exposure to an actual service environment may lead to microstructural degradation of the concrete surface. Therefore, the retained long-term dam concrete samples need to be further researched to better understand its microstructural evolution and development of its properties.