Siegfried Siegesmund - Monument Future

In particular, because sedimentary rocks, such as fossil sites, contain clay minerals and basically have a high hygroscopic property, physical damage can occur due to the pressure generated by repeated swelling and shrinking. Furthermore, it is also necessary to restrain both swelling and surface hardening.

Accordingly, Lee (2009) conducted various tests by applying different types of consolidation reagents to sedimentary rocks and suggested that Wacker’s SILRES ®BS OH 100 and Remmers’s Funcosil ®KSE 300 were the best reinforcing products ( Table 1). OH 100 is a colorless, or a pale-yellow, liquid substance containing almost 100 % ethyl silicate and its density is approximatley 0.99 g/cm 3at room temperature (25 °C). KSE 300 is a colorless, very 200light-yellow liquid substance with approximately 40 % ethyl silicate, and its density is approximately 0.92 g/cm 3at 20 °C. Like OH 100, it can be applied to pores of all sizes, and gels are formed efficiently at temperatures between 10 °C and 20 °C to help strengthen rocks.

Table 1: Comparison of the properties of consolidation reagents in trial experiment.

Additionally, preceding research has reported a mechanism of anti-swelling agents that prevents the clay minerals from swelling and shrinking. As a result of the reaction experiments with OH 100 and KSE 300, it was also found that the anti-swelling agent is adsorbed by the surface of mineral particles; furthermore, it plays a buffer role, reducing changes occurring during the curing period of the consolidation reagents. The anti-swelling agent used in this process was Funcosil ®Antihygro, which is manufactured by Remmers and is a colorless liquid substance with a density of approximately 1.0 kg/L at 20 °C (Lee, 2009).

Although the preceding research has verified the effect of both consolidation reagents and anti-swelling agents, the effect of restoring the rocks’ physical properties may vary depending on the rocks’ characteristics when two types of preservatives are used together and used outdoors. Therefore, this study collected a boulder stone (which was the same type as the parent rock of the dinosaur egg fossils in Gojeongri, Hwaseong) in order to conduct indoor reinforcement experiments; the boulder was made into sixteen test pieces, each with a size of 5 × 5 × 12 cm (width × length × height). The test pieces were classified into four groups: A, B, C, and D; the chemicals whose reinforcing treatment effect was verified in the preceding research were applied to each group. After applying OH 100 to A, KSE 300 to B, anti-swelling agents and then OH 100 to C, and anti-swelling agents and then KSE 300 to D, each group’s treatment effects were compared (Fig. 3). To evaluate the physical properties of study subject, the ultrasonic velocity of the specimen was measured by the direct method. This method is optimal because the degree of the pulse energy transfer between transmitter and receiver is typically excellent, allowing for the reliable acquisition of P-wave velocity values (Lee et al . 2017). The factors measured to examine the treatment’s effectiveness are: the specimen’s weight, color difference, chromaticity, and ultrasonic velocity variation (Fig. 4).

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.