Читать книгу Monument Future - Siegfried Siegesmund - Страница 304

As a result of the deterioration assessment of all of the fossil sites, cracking, peeling, and chipping were observed in most areas, with cracking especially prominent. Additionally, the damage patterns varied by fossil sites. In particular, the Mumyeongsom, Nudebawee, Sanghanyeom, and the Gaemesom sites were identified as places where special treatments should be performed because the dinosaur egg fossils were highly likely to be lost in the future.

Figure 3: Test set up for monitoring reinforcement. (left) Experimental specimen, (right) Impregnation of specimens with reinforcing agent.

The rocks that constitute the fossil site are quartz wacke. Furtherore, the analysis of mineralogical 201properties showed that major rock-forming minerals were as follows: illite, plagioclase, mica, quartz, alkali feldspar, and calcite.

Figure 4: A test on the physical properties of specimen. (left) Ultrasonic measurement point, (right) Ultrasonic measurement method.

A P-XRF analysis was performed on the Nudebawee site by dividing contaminants into outcrops, soil deposits, and dinosaur eggs. The matrix layer had a slightly higher Fe level than other components, while the soil deposits showed little difference from the matrix layer. The dinosaur eggshells revealed a slightly high Ca level, while Cl was not detected except for one spot (Fig. 5).

Figure 5: Measurement results by P-XRF of the contaminants in the dinosaur egg fossil sites from Hwasung Gojeongri.

With an average ultrasonic measurement for all of the fossil sites of 1,987 m/s, all the fossil sites showed low ultrasonic 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.