The South-to-North Water Diversion Project involves a large investment, a long route, and numerous individual projects. Among them are channels, bridges, culverts, pipelines, inverted siphons, and aqueducts that are constructed with concrete panels. The project has a complex structure, diverse forms, a large exposed area, and is vulnerable to erosion from adverse external environments. Therefore, both the concrete panels and various concrete structures possess durability. 

The durability of concrete refers to the property of concrete, when meeting the design requirements, resisting the effects of environmental factors and remaining undamaged after long-term use. If the durability is insufficient, it will cause varying degrees of damage to the structure. Once damaged, the investment of manpower and material resources for repair is often very large. Therefore, improving the durability of concrete has important practical and long-term significance for extending the service life of concrete buildings and saving national investment. 

The causes of damage and deterioration of concrete include external environmental conditions, internal defects in the concrete, and the composition materials of the concrete. External environmental conditions include meteorological factors such as wind, rain, sunlight, temperature changes, dryness and humidity, erosion, chemical medium erosion, etc.; internal defects include the penetration of concrete and alkali-aggregate reaction; composition materials include volume changes caused by the different thermal properties of aggregates and cement paste. The external environment is an objective fact and is almost impossible to change. Therefore, improving the durability of concrete should start by reducing internal defects in the concrete and improving its composition materials, in order to improve the performance of the concrete, enhance the quality of the concrete, reduce or eliminate internal defects in the concrete, and extend the service life of the concrete structure.