4:00 PM - 4:15 PM
[HTT21-03] Conservation restoration of the world heritage of Okinawa Prefecture, Sonohyan-utaki Ishimon - Situation after 30 years since filling with mortar and applying silicone resin.
Keywords:Stone cultural heritage, Restoration, Okinawa , Limestone, Colorimeter
In order to understand the color of the surface of the repaired roof and the overall color of the stone gate, quantitative measurements were made using a spectroscopic colorimeter (Konica Minolta, CM-700d) at 51 locations on the surface of the stone gate. The proportion of blackened parts was determined from the front of the stone gate using Photoshop. To measure the surface temperature of the stone gate, we grasped the temperature distribution of the surface using the FLIR thermal camera.
We installed a button type temperature and humidity measuring instrument in the upper left side of the stone gate with the permission of Naha City to grasp the change of temperature and humidity in the year-round. As a result of the measurement by the spectrophotometer, the color of limestone was bright, and it was almost the same color as the repair material in the roof part. However, the discoloration rate and the situation were different after 30 years. The repair material was gray, and it was found that the original stone was darker. The average annual temperature observed under the roof of the stone gate was 24 °c, and the average humidity was 81.5%, and the characteristics of the hot and humid subtropical climate were observed. The average temperature in winter was 22.1 °c, and the humidity was 80% and the lowest temperature was 8.5 °c. Therefore, it seems that the growth of vegetation is very fast and it may affect the color of rock surface.