In this study, we combine clustering of images obtained by passive infrared thermography method and heat balance analysis for the non-contact evaluation method of subsurface damage of dam concrete. It is possible to classify the concrete, efflorescence, chalk, joint and vegetation from obtained visible and thermal images by image clustering. Heat balance analysis is applied for the classified concrete part, the void and non-damaged surface temperature could be reproduced with an MAE (Mean Absolute Error) of 1.5°C. These results indicate that it is possible to reveal the relationship between concrete surface temperature and subsurface damage situation. This method is expected to apply to the quantitative evaluation of subsurface damage.

Aso Tateno Dam is a curved gravity concrete dam that incorporates the design concept of an arch dam, which transmits water pressure acting on the dam to the rocks on both sides. Since it was not possible to fill construction joints or place cooling piping, The columnar construction method in which the dam body is divided into blocks and concrete is placed in layers, was adopted for the first time in about 20 years. We will report on concrete cooling pipe cleaning and joint grouting for construction joints, which are rarely performed in the currently mainstream surface construction methods, and our efforts to improve efficiency.