wave velocities under 3,000 m/s. The relatively weathering indices of the sites were estimated between the moderately weathered (MW) stage and the completely weathered (CW) stage, while the majority of the sites belonged to the highly weathered (HW) stage, relatively. Meanwhile, the Hanyeom and Gaemesom sites had higher shares of CW than other regions, which is considered a result of their relatively longer exposure periods.
On the damaged parts of rock matrix that have cavities and cracks (such as blistering), the thermal conductivity and density decrease, resulting in changes in the heat transfer coefficient and thermal conductivity, compared to healthy parts. Additionally, the air layer created by such defects has a very small volumetric heat capacity, which causes it to respond to external temperatures with sensitivity. As a result, the damaged parts are heat up faster and cool down more slowly than healthy parts. In the thermal image, the healthy part is blue because its temperature does not increase more easily than its exfoliated part, which is red. 202Thus, the infrared thermography analysis of the scalingoff elements at the fossil sites revealed a distinct difference in thermal distribution between dinosaur egg fossils and the surrounding rocks (Fig. 6).
Figure 6: Thermographic images showing representative blistering zones of the dinosaur egg fossil sites in Hwasung Gojeongri.
The indoor reinforcing test performed to select a consolidation of reagents suitable for the study subjects revealed that Wacker OH 100 had the least difference in color from the original rock and the highest increase in ultrasonic wave velocity after the anti-swelling treatment, indicating the greatest effect in strengthening the specimens’ physical properties. Additionally, the SEM-EDS analysis of two dinosaur egg specimens from each group before and after reinforcing revealed that both specimens had substances similar to limestone; this implies that the consolidation reagents generally used for limestone, Remmers KSE-300 H/V, would be proper for consolidant treatment.
The conservation treatment for the fossil sites was conducted by selecting three sites around the fossil sites and classifying them into supplementing and reinforcing cracks. As a result of supplementing cracks using epoxy type L-30, L-50 and KSE-500, L-30, the treatement revealed a relatively better effect in strengthening the physical properties than the other two adhesives. OH 100 and KSE 300 showed a similar effect; after conducting a pre-treatment of anti-swelling and applying two types of consolidation reagents three times, it was found that OH 100 was relatively stable.
The measuement of ultrasonic wave velocity at each site was performed to monitor the effect of the trial preservation treatment and revealed that the average values before the treatment(2,091 m/s) was increased to 2,394 m/s after the treatment. In particular, the Sanghanyeom-21, Hanyeom-30, and Gaemesom-31, which had belonged to the CW stage, were upgraded to the HW stage due to the ultrasonic wave velocity increase after the preservation treatment. Although a short-term effect can be expected for outdoor fossil sites, it seems necessary to apply additional measures, coupled with a conservation treatment, in the long run (Fig. 7).
Figure 7: Trial conservation treatments and monitoring for effects of the dinosaur egg fossil sites in Hwasung Gojeongri. (left) Resin treatments within the cracks, (middle) Reinforcing the surface and (right) Effect monitoring by ultrasonic velocity.
References
Lee, C. H. and Jo, Y.H, 2017, Correlation and correction factor between direct and indirect methods for the ultrasonic measurement of stone samples, Environmental Earth Science, 76:477.
Lee, Y. N., Jeong, K. S., Chang, S. K., Choi, M. Y., Choi, J. I., 2000, The preliminary research on the dinosaur eggs and nests found in the reclaimed area south to the Siwha Lake, Gyeonggi Province, Korea, Journal of the Paleontological Society of Korea, 16(1), 27–36. (in Korean with English abstract)
Lee, Y. N., 2003, Dinosaur bones and eggs in South Korea. Memoir of the Fukui Prefectural Dinosaur Museum, 2, 113–121.
Lee. S. J., 2009, Study on the consolidating mechanism of stone monuments containing clay minerals with swelling properties. Ph.D. Thesis, Kyeongju National University, 1-110 (in Korean with English abstract).
Zhao, Z. K., and S. R. Ding. 1976. Discovery of the dinosaur eggs from Alashanzuoqi and its stratigraphical meaning, Vertebrata PalAsiatica, 14, 42–44.
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MATERIAL CHARACTERISTICS AND NON-DESTRUCTIVE DIAGNOSIS OF STONE STANDING BUDDHA AND STONE CHAMBER OF MIREUKRI TEMPLE SITE IN CHUNGJU, KOREA
Hee Young Park1, Sun Young Park2, Chan Hee Lee2*, Jun Hyoung Park2
IN: SIEGESMUND, S. & MIDDENDORF, B. (EDS.): MONUMENT FUTURE: DECAY AND CONSERVATION OF STONE.
– PROCEEDINGS OF THE 14TH INTERNATIONAL CONGRESS ON THE DETERIORATION AND CONSERVATION OF STONE –
VOLUME I AND VOLUME II. MITTELDEUTSCHER VERLAG 2020.
1 Chungbuk Research Institute of Cultural Heritage, Cheongju, 28443, Republic of Korea
2 Dept. of Cultural Heritage Conservation Sciences, Kongju National University, Gongju, 32588, Republic of Korea
Abstract
The Stone Standing Buddha and the Stone Chamber of Mireukri temple site in Chungju is a semi-built artificial stone grotto temple that inherited the Gyeongju Seokguram Grotto (AD 751) in South Korea. It was designated as Korean Treasure No. 96 in recognition of its value as a cultural heritage site like the huge Stone Standing Buddha (10.6 m in height), a unique architectural structure.
However, the Stone Chamber had problems with its structural stability as its masonry was constructed after being built on top of weathered granite, where the original ground sloped to the west. Due to continuous creep, the structural deformation was clearly visible in the western wall of the Stone Chamber in 2014, which was decided to be dismantled in 2016. Currently, the dismantling and repair work is in progress on all sections of the western wall and some sections of the southern wall.
With the repair work, an overall conservation scientific investigation including non-destructive diagnosis for the Stone Standing Buddha and Stone Chamber was carried out. As a result, the main rocks that make up this study subject are pinkish medium-grained biotite granites, which as Wolaksan granite. The deterioration assessment on the Stone Standing Buddha indicated moderate conditions for all types of damage. However, in the analysis of surface contaminants, there was a singularity that the content of lead on the statue’s face was measured to be relatively higher than other parts.
The physical evaluation by ultrasonic velocity showed third grade deterioration (moderately weathered – MW) in the Stone Standing Buddha, while the Stone Chamber
