Abstract: In order to understand the expansion and deterioration of concrete in macro-and-micro senses,we took the alkali activity of sandstone aggregate of a large hydropower station in China as research background. In consideration of practical engineering demands, we carried out long-age simulation test on fully-graded mass concrete alkali aggregate reaction using SEM (Scanning Electron Microscope) test technology, and in association with the existing assessment system for alkali aggregate reaction, we researched the long-term inhibition of alkali activity. Results suggest that the characteristics of reaction product can be observed evidently by using SEM, the reaction degree can be obtained semi-quantitatively, and the trend of concrete deterioration can be estimated.

Key words: hydropower station, SEM, concrete alkaline aggregate, fully-graded, alkali activity, experimental research