Читать книгу Monument Future - Siegfried Siegesmund - Страница 303

This study conducted a non-destructive precise diagnosis to comprehensively examine the conservation status of the fossil sites, through which conservation schemes were established. To this end, the mineralogical characteristics of the fossil sites were analyzed, and a surface deterioration assessment and a test on the constituent rocks’ physical properties were carried out.

Furthermore, the damage types were recorded at the site to identify the damage type, location, and distribution of rocks generated by locality at the fossil site. Based on these recordings, a damage map was drawn up and quantitative damage rates were estimated. For blistering, which is difficult to observe with the naked eye, the location and actual area were determined by using both infrared thermography and a percussion technique. The infrared thermal imaging camera used in the analysis was FLIR’s T640 model. Thermographic images were obtained through an active method of detecting the blistering that is caused by instantaneous temperature changes due to artificial heat; a near-infrared electric heater was used as the heat source.

Additionally, ultrasonic measurements were performed to evaluate the properties of the research sites and dinosaur egg fossils. Pundit Lab, which is manufactured by Proceq, was used for evaluation. After converting the measured ultrasonic velocity into a weathering index, an image map was drawn up using the Kriging technique. Through this, the fossil site’s overall weathering status was investigated. Moreover, the petrographic characteristics were examined by using P-XRF (Oxford, JSM 6335F) to analyze the contaminants on the fossil surfaces and to determine the causes of weathering.

Based on these findings, the direction for the fossil site’s preservation was determined, and its effect was verified through an indoor reinforcement treatment test and a field application experiment prior to actual treatment. Additionally, a general reinforcement treatment was performed, including on cracks for the areas that required preservation; supports were also installed to mitigate structurally weak elements. Furthermore, monitoring was conducted to verify the preservation treatment’s effects. The data collected from each non-destructive device was immediately put together in the field to verify the data’s reliability. Based on this, the comprehensive precision safety diagnosis of the dinosaur egg fossil site at Gojeongri, Hwaseong, was reviewed.

Additionally, a trial experiment was performed to select a proper consolidation reagent to preserve the fossil sites’ rocks, whose physical properties had been weakened by weathering. The natural heritage consisting of rocks (such as fossil sites) is weathered by complex factors, including physical, chemical, and biological elements when rock matrix are exposed outdoors. Likewise, a stone cultural heritage consisting of rocks is also weathered by various factors; when the rock surface strength has deteriorated, it is common to apply a surface treatment to restore the rock’s physical properties.

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/cm³ at 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/cm³ at 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).