Monument Future

References

D’ham G., Meinhardt J., Niemeyer R. 2010. Bestimmung der kapillaren Wasseraufnahme mit Messröhrchen nach Karsten und Mirowski. In: Auras M., Meinhardt J., Snethlage R. (eds) Leitfaden Naturstein-Monitoring; IRB-Verlag, Stuttgart, pp 82–92.

Fitz C., Krus M. 2004. Normenwirrwarr bei der Bestimmung von feuchtetechnischen Materialkennwerten. IBP-Mitteilung 441, 31 (2004) Neue Forschungsergebnisse kurz gefasst. Fraunhofer-Institut für Bauphysik.

Hendrickx R. 2013. Using the Karsten tube to estimate water transport parameters of porous building materials. The possibilities of analytical and numerical solutions. In: Materials and Structures 46/2013, pp 1309–1320.

Karsten R. 1960. Bauchemie für Schule und Baupraxis. 1. Aufl., Straßenbau, Chemie und Technik Verlagsgesellschaft mbH, Heidelberg, pp 381–382.

Karsten R. 1997. Bauchemie. Handbuch für Studium und Praxis. 10. Aufl., C. F. Müller Verl., Heidelberg, pp 397–404.

Künzel H. 1969. Anforderungen an Außenanstriche und Beschichtungen aus Kunstharzdispersionen. In: Kunststoffe im Bau 12, Heidelberg, pp 6–32.

Künzel, H. 1971. Gasbeton. Wärme und Feuchtigkeitsverhalten. Bauverl., Wiesbaden/Berlin.

Lykow A. W. 1958. Transporterscheinungen in kapillarporösen Körpern. Akademieverl. Berlin.

Pleyers G. 1999. Zerstörungsfreie Prüfung der Flüssigkeitsaufnahme von Baustoffen – das Prüfröhrchen nach Pleyers. In: 5. Internationales Kolloquium, Werkstoff-wissenschaften und Bauinstandsetzen, Esslingen, Nov./Dez. 1999, Aedificatio Publishers: Freiburg, pp 471–484.

Rucker-Gramm P. 2008. Modellierung des Feuchte- und Salztransports unter Berücksichtigung der Selbstabdichtung in zementgebundenen Baustoffen. PhD thesis, Technische Universität München.

Schwarz B. 1972. Die kapillare Wasseraufnahme von Baustoffen. In: Gesundheits-Ingenieur 93/1972, H. 7, pp 206–211.

Schwarz B., Künzel, H., Gösele K. 1971. Die kapillare Wasseraufnahme von Baustoffen. Forschungsauftrag des Bundesministeriums für Städtebau und Wohnungswesen durchgeführt in der Außenstelle Holzkirchen des Instituts für Technische Physik der Fraunhofer-Gesellschaft, Stuttgart/Holzkirchen.

Snethlage R., Pfanner M. 2013. Leitfaden Steinkonservierung. Planung von Untersuchungen und Maßnahmen zur Erhaltung von Denkmälern aus Naturstein. 4. Aufl., Fraunhofer IRB Verl.

Snethlage R., Wendler E. 1995. Methoden der Steinkonservierung – Anforderungen und Bewertungskriterien. In: Snethlage, R. (eds) Natursteinkonservierung in der Denkmalpflege. Arbeitshefte des Bayerischen Landesamtes für Denkmalpflege, Bd. 80, Verlag Ernst & Sohn, Berlin, pp 3–40.

Wendler E., Snethlage R. 1989. Wasseraufnahmeprüfer nach Karsten – Anwendung und Interpretation der Messwerte. In: Bautenschutz und Bausanierung 12/1989, Verl. Rudolf Müller, Köln, pp 110–115.

293

EVALUATION ON REUSABILITY AND DAMAGE OF STONE PROPERTIES FOR REPAIR OF WOLNAMSAJI TEMPLE SITE STONE PAGODA FOR GANGJIN KOREA IN 13TH CENTURY

Seok Tae Park, Sung Han Kim, Chan Hee Lee

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.

Dept. of Cultural Heritage Conservation Sciences, Kongju National University, Gongju, 32588, Republic of Korea

Abstract

Researchers have generally worked hard to manage ancient masonry buildings and continually assess their conservation status. If a structural problem exists in monuments, investigation of the problem is not difficult. However, its long-term management is difficult as it is not easy to accommodate the absence of old structures. Therefore, it would be very efficient to possess a method that could present data which could easily determine the whole situation.

The three-storyed stone pagoda in the Wolnamsaji temple is located in Gangjin, Republic of Korea. All the stone properties were recently dismantled following the identification of structural problems. In this study, reuse evaluation and nondestructive analysis were performed on the dismantled stone pagoda members. Although nondestructive tests have been previously performed by researchers, robust assessments of their conservation status have not been performed.

Our goal was to facilitate management of the stone pagoda members via a detailed investigation and develop a conservation management plan. The management plan provides basic data for accurately identifying the condition of each stone pagoda member and devising stable and long-term management measures even after proper decomposition and reassembly. Additionally, these results can facilitate restoration of the stone pagodas based on their original form and establishment of proper conservation and treatment measures for damaged stone properties.

Keywords: Nondestructive diagnosis, Stone pagoda, Wolnamsaji temple, Conservation management card

Introduction

The Wolnamsaji temple located in Wolnamri in Gangjin, Republic of Korea, is currently only composed of stone pagodas. Specifying the exact chronology of Wolnamsaji temple remains difficult because there are no clear literature records on when it was founded and when it fell into disrepair.

In Buddhism, stone pagodas have been built in various ways, generally in the shape of bricks. This was the style of the Baekje Kingdom that ruled ancient Korea from 18 BC to 660 BC. In southern Korea, Baekje-style stone pagodas are rare and have high historical and academic value.

Currently, stone pagodas require comprehensive inspections as they have not received special care 294for a long time. These inspections involve a thorough investigation of the cracks, fractures, discoloration, and other structural damages that have recently appeared.

After a thorough investigation of the pagodas, structural problems caused by damage to the basement and loss of filling stones were determined, followed by conservation and repair. Dismantled rock properties require systematic and scientific review for repair. In this study, conservation and scientific data were collected through physical diagnosis and check whether the stone should be reused for restoration.

Our results can be used for the repair and restoration of the stone pagodas based on the original rocks and the establishment of conservation strategies for damaged stone pagodas. Moreover, our results provide basic data that help establish stable, long-term conservation schemes (Fig. 1).

Figure 1: Photographs showing the stone pagoda in Wolnamsaji temple site. (left) Before dismantling the pagoda, (right) Stone properties after dismantling the pagoda.

Materials and Methods

In this study, all members of the dismantled Wolnamsaji temple pagoda were investigated to classify the rocks and summarize the characteristics of each rock. Based on these results, the site of each stone was reviewed by exploring the same types of rock that make up the stone pagoda. Special attention was given to Wolchulsan Mountain located near the Wolnamsaji temple site.

With the increased interest in the repair and restoration of stone cultural properties, several conservation science studies have been conducted with old structures (Lee and Lee, 2009; Chun et. al., 2013; Jo and Lee, 2015). Additionally, surface damage assessment, nondestructive physical properties, and precision diagnoses were performed to comprehensively identify damage and assess whether each component could be reused for restoration.

In the surface damage assessment, the types of damage sustained by cultural assets were broken down and a comprehensive damage map was drawn based on them. Afterward, weathering phenomena were described in detail and quantified to calculate the damage (Fitzner et al., 2003).

In the non-destructive analysis, stone exfoliation was difficult to identify with the naked eye; therefore, the location and extent of exfoliation were confirmed by infrared ray thermal analysis and compared with the damage map. In addition, component analysis was conducted using P-XRF for contaminants on the surface of cultural assets, and a physical diagnosis, which could be the most important criterion for reviewing the reuse of stone pagoda members, was conducted with ultrasonic measurement.

Specifically, a conservation management plan was prepared by integrating surface damage assessment with nondestructive precision diagnosis. Moreover, we presented a review of the reuse and treatment plan for the condition of each member.

295Results and Discussion

In total, five types of granite and one type of tuff were examined in the Wolnamsaji stone pagoda. These rocks are believed to have been used regardless of the location, size, and purpose of members in the construction. The rock of the pagoda is pink feldspar granite that accounts for a large number of its stone properties. Major rock-forming minerals included quartz, plagioclase, and orthoclase (Fig. 2).

Figure 2: Microphotographs showing the stone surface (left) and polarizing microscope image (right) on the pink feldspar granite used host rock of the pagoda.

The material properties of the rock constituting the stone pagodas and the possibility of their mountain of origin were analyzed by conducting a detailed survey of the distribution of homogenous rock species in Wolchulsan Mountain near the stone pagodas.

Six types of rock that were deemed to compose the stone pagoda were also identified near the Wolnamsaji temple site. Specifically, coarse-grained equigranular pink feldspar granite that accounted for the largest proportion of stone overlapped with the magnetic susceptibility of 3.80 × 10⁻³ SI units.

Cracks and interval gaps were identified in the members of the stone pagoda (Fig. 3).

Moreover, granular disintegration was evident, specifically in the pronounced vertically oriented structural cracks. Discoloration from contaminants due to chemical and biological damage on the rock surface was conspicuous; indeed, many members had > 50 % of their surfaces cladded. Detection of surface exfoliation through infrared thermal photography analysis showed that > 15 % of the surface was stripped (Titman, 1990; Kern, 2008; Jo and Lee, 2014) (Fig. 4).

Pronounced internal detachment was also observed in ultrasonic velocity measurements on all stone properties, which showed that due to the various damage, many members were vulnerable even though the mean properties were adequate. Examined members showed relatively high surface damage rates and degraded properties on the mating faces. Therefore, careful conservation and post-treatment reassessment are required for reuse(Iliev, 1966; Kahraman, 2002; Lee and Jo, 2017) (Fig. 5).

It would be particularly advantageous to develop conservation strategies that can specifically address damage such as the separation or cracking of thin layers created on the surface to impede the further development of structural vulnerabilities.

The main discoloration factor of contaminants on the stone surface was shown to be Mn. The red contaminant Fe that was identified as corrosion from a fixed iron piece was detected at fourfold greater levels in the corroded parts than the fresh parts.

To determine whether to reuse or replace members, three evaluation factors must be checked in total. First, the surface damage rating of members was determined by performing a surface damage evaluation through the damage rate. The evaluation grades were graded as 0–5 where the more progressive the cracks and peelings, the higher the grade. However, since it is difficult to clearly identify the strength of a member from just the 296surface weathering grade, additional review is necessary to reflect the results of physical property diagnosis.

Figure 3: Representative physical damages to the stone surfaces of the pagoda. (left upper) Deep cracks on the surface, (right upper) Surface exfoliations, (left lower) Broken the corner, (right lower) Granular degradation on the surface.

Figure 4: Representative thermographic images by the damage types on the stone properties in Wolnamsaji temple sites. (left upper) Multi-cracks on the surface, (right upper) Multi-fractured on the surface, (left lower) Surface exfoliations (right lower), Granular degradation on the surface.

The physical property diagnosis of members was judged based on the results of ultrasonic measurement. The judgment criteria are level 1–5 where the lower the measured ultrasonic velocity, the higher the classification and vice versa. However, since there are weak parts in each member and the influence of the loads received by the members 297differs, members that were judged as 4–5 warrant re-evaluation even after strengthening.

Figure 5: Ultrasonic modeling results of the members to be joined, and it can be confirmed that the velocity of each member is different and that the vulnerable zone exists.

For a comprehensive review, the surface weathering grade and property grade were synthesized to set the conservation management grade and determine whether to reuse the member. The evaluation grade was divided into six stages of 0–5, as in the surface weathering grade. At Level 1, a member can be reused without preservation; at level 2 or above, the member will need preservation and monitoring such as cleaning, bonding, structural reinforcement, and strengthening depending on the surface weathering and physical properties.

Those members classified as stage 5 cannot be reused and should be replaced with new stone that can then be classified as stage 0. This reinforcement system is a very important process for the preservation and management of stone even when the stone tower will be repaired in the future. In particular, when the surface weathering degree and physical property grade differed, the degree and location of physical and structural damage were judged to be the most important factors in setting the conservation management level.

Overall, based on the degree of damage to members of the stone pagodas, 176 out of the total 200 stone properties (88.0 %) were deemed reusable; only 12 (6.0 %) were deemed nonreusable.

Most of the member surfaces were discolored and required surface cleaning, adhesion, and charging to the cracks and detachment. Specifically, stone pagoda members bearing significant damage that were going to be reused would have reduced material strength at each joint face, requiring careful conservation treatment and reevaluation after treatment.

The 12 nonreusable stone members with the same shape, size, and rock-based properties should be further examined. At this time, a materiality review using ultrasonic or rebound hardness measurements should be conducted to assess their utility as restoration stones.

The conservation management plan involves regular or continuous monitoring of the pagoda and provides guidelines for understanding any changes in the conservation status. All the research and evaluation conducted in this study can be prepared using the conservation management plan for each member and basic data for developing stable and long-term management schemes even after reassembly.

298References

Chun, Y. G., Lee, C. H., Jun B. K., 2013, Lithological characteristics and provenance interpretation of Jinyangri Gakgol Dolmen in Hampyeong of Korea. Journal of the Geological Society of Korea, 49, 517–526. (in Korean with English abstract)

Fitzner, B., Heinrichs, K. and La Bouchardiere, D., 2003, Weathering damage on Pharaonic sandstone monuments in Luxor-Egypt. Building and Environment, 38, 1089–1103.

Iliev, I. G., 1966, An attempt to estimate the degree of weathering of intrusive rocks from their physical-mechanical properties. Proceeding of International Congress on Rock Mechanics, 1, 109–114.

Jo, Y. H., Lee, C. H., 2014, Quantitative modeling of blistering zones by active thermography for deterioration evaluaton of stone monuments. Journal of Cultural Heritage, 15, 621–627.

Jo, Y. H., Lee, C. H., 2015, Analysis of ancient document and establishment of petrological database for presumption of stone source area of the Seoul City Wall, Korea. Journal of the Petrological Society of Korea 24, 193–207. (in Korean with English abstract)

Kahraman, S., 2002, Estimating the direct P-wave velocity value of intact rock from indirect laboratory measurements. International Journal of Rock Mechanics & Mining Sciences, 39, 101–104.

Kern, C. D., 2008, Evaluation of infrared emission of clouds and ground as measured by weather satellites. Ph.D. Thesis, University of Washington. 1–61.

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 Sciences, 19, 76:477.

Lee, M. H., Lee, C. H., 2009, Transportation route, provenance and petrological characteristics of the Five-storied stone pagoda in the Seongjusaji temple site, Korea. Journal of the Geological Society of Korea 45, 725–739. (in Korean with English abstract)

Titman, D. J., 1990, Applications of infra-red thermography to civil engineering problems. The British Journal of Non-destructive Testing, 32, 149–154.299

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LONG-TERM MONITORING OF STONE MONUMENTS AND BUILDINGS

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303

CHALLENGES OF INVESTIGATING DECAY IN AN ENCLOSED BEDROCK MONUMENT: FOSSIL GROVE, GLASGOW

Sarah Hamilton1, Callum Graham1, Christa Gerdwilker2, James Hepher¹, Sophia Mirashrafi¹, Ewan Hyslop3

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.

Historic Environment Scotland, Conservation Directorate, UK

1 The Engine Shed, Forthside Way, Stirling, FK8 1QZ

2 South Gyle Conservation Centre, 7 South Gyle Crescent, Edinburgh, EH12 9EB

3 Longmore House, Salisbury Place, Edinburgh, EH9 1SH

Abstract

Fossil Grove Site of Special Scientific Interest (SSSI) comprises the fossilised remains of 325 million year old Lycopod trees and their root systems, uniquely preserved in their growth positions. Encapsulated in a brick building after discovery, age and lack of regular maintenance have taken their toll, and the condition of the fossils is now of concern due to salt growth and excessive condensation. A program of ongoing work aims to arrest the current decay and stabilise conditions, while developing recommendations and tools for long-term management. Three key approaches of this multidisciplinary investigation are described: (i) identifying the salts affecting the fossil floor; (ii) understanding internal conditions and water movement; (iii) creating a risk map tool to manage impact on the fragile fossil floor. The paper highlights the challenges of addressing these issues in relation to a bedrock monument constrained within a poorly maintained building affected by natural groundwater ingress, high humidity and financial and political constraints.