연구과제 요약 과제 고유번호 사업명 과제명 공개가능여 자동부여 부 석조 문화재 손상제어기술연구 석조 문화재 손상원인 규명 및 저지기술 개발 (석조문화재 보존처리제 개발) 성 명 강 용 수 주민등록번호 연구책임자 소속 기관명 한양대학교 화학공학과 전자우편 kangys@hanyang.ac.kr 전화번호 02-2296 - 2336 연구목표 (400 ~600자) 강화제 처리 전후 암석의 광물학적 변화 분석 및 규명하고 2007년도에 R&D를 통해 개발된 표면강화제의 효율 및 안정성에 대한 현장 평가를 실시하였다. 또한 2007년 연 구 성과에 대한 현장 적용성 및 암석에 미치는 영향과 결과에 대한 성과 및 효율성 검토하여 실제 문화재 적용하였을 때 기대할 수 있는 결과를 도출하였다. 알콕시 실란 작용기를 가지는 비닐 단량체의 혼합사용으로 무기친화성이 개선된 보 존처리제의 최적 조성을 선정및 신선한 화강암과 사암에 가암함침 처리 및 평가하여 성능개선 여부를 파악하고자 하였다. 또한 신선한 화강암, 사암 그리고 실제 풍화된 석재에 보존처리제를 함침처리하여 내염, 내산성시험, 가속풍화시험 및 실 현장 평가 등을 통해 처리제와 처리방법의 안정성(내구성)을 검증하고자 하였다. 새로운 에폭시 접착제 개발에 대한 연구는 침투성 향상을 위한 새로운 에폭시 수지 를 개발하고자, 나노 기공을 가진 나노 소재를 이용하여 풍화된 석재에 적용 가능한 황변이 없는 에폭시 접착제를 개발하는데 주력하였다. 또한 2000년도 이전에 에폭시 접착제가 기 처리된 문화재를 선정하여 현장 방문, 시료 채취 및 정량 분석을 통해, 사 용된 접착제의 적용 안정성과 2차 손상 위험에 대한 검토 및 평가를 실시하였다. - 281 -
연구내용 (1000~1200자) 기 개발된 표면 강화제를 화강암, 사암, 대리암에 적용시킨 후 암석 광물학적 특성 변화를 연구하기 위하여 상용화된 제품 및 기 개발된 강화제를 화강암, 대리암, 사암 에 적용하여 강화제의 효율 및 안전성에 대한 현장평가를 실시하였다. 기 개발된 강 화제의 현장적용기술은 2007년도에 R&D를 통하여 개발한 기술을 적용하였으며, 처 리 전 후에 초음파측정, 슈미트헴머 경도측정, 색도 측정을 실시하였다. 가압함침을 통한 석조물의 보존처리법에 사용되는 처리제의 무기친화성의 개선을 위해 siloxane 작용기를 가진 아크릴계 단량체를 공단량체로 사용하고자 하였고, 그에 따른 조성 및 중합조건 등을 유리전이온도, 인장강도 등을 기준으로 최적화하였다. 또한 화강암, 사암 등에 개선된 보존처리제를 가압처리하여 이전 처리제와 처리 후 나타나는 물리화학적 성질 및 기계적 성질의 효과를 비교 평가 하였다. 특히 개발된 보존처리제 및 처리방법의 장기안정성 검토를 위해 가압함침 처리 시편의 내염성과 내산성 시험뿐만 아니라 가속풍화시험 및 실 현장 평가를 통한 내구성 평가를 수행 하였다. 석조 문화재 접착제를 개발하는데 있어, 외부 노출 시 색이 변하는 기존 접착제와 차별하여 색 안정성이 있고, 화강암 석재의 성분과 비슷하고 통습성을 갖는 나노 기 공 소재를 합성 및 준비하여 형태 안정성 및 접착 강도를 조절한 에폭시계 접착제를 개발하였다. 더 나아가 침투도 및 암석의 2차 손상이 일어나지 않는 에폭시계 수지의 점도 및 강도에 대한 연구를 진행하였다. 또한 나노 기공 소재의 특성, 농도별 접착 특성을 확인, 접착 강도와의 상관성을 분석하고, 개발된 접착제는 화강암, 사암, 대리 암에 적용하여 특성을 분석하였다. 국내 석조 문화재에 서기 2000년 전에 기 처리된 문화재를 선정하고, 현장 방문 및 시료 채취를 하여, 사용된 접착제의 특성 분석과 비교하여 적용 안정성을 평가하고, 평가 방법을 개발하였다. - 282 -
총괄 참여연구원 성 명 주민등록번호 성 명 주민등록번호 강용수 김연철 원종옥 김정진 김형중 채진석 고홍석 정영은 최수정 유순동 김은경 민정식 유충석 최승원 김준영 강 한 이동기 김수진 박수일 이정현 오 혁 채일석 손승환 강덕기 암석과 광물, 화강암, 사암, 대리암, 에폭시 접착제, 한글 Keywords 카 소재, 가압함침, 무기친화성, (5개 내외) 나노 기공 실리 rock and mineral, granite, sandstone, marble, epoxy consolidant, si 영문 nanoparticle, pressurized impregnation, inorganic affinity - 283 -
Conservation M ethods of Silicate Consolidants for Weathered Granites Jung Hyun Lee 1 and Su-Jin Kim 1, Yong Soo Kang 1, Un Young Kim 1, Jeong Jin Kim 2, Jongok Won 3 and Sa Duk Kim 4 1 Department of Chemical Engineering, Hanyang University, Seongdong-gu, Seoul 133-791, S. Korea (kangys@hanyang.ac.kr) 2 Department of Earth and Environmental Science, Andong University, Andong, Kyungbuk, S. Korea 3 Department of Chemistry, Sejong University, Kwangjin-gu, Seoul 143-747, S. Korea 4 National Research Institute of Cultural Heritages, Conservation Science Division, Yuseong-gu, Daejeon 305-380, S. Korea Abstract : A novel consolidation method was proposed to increase the penetration depth of silicate consolidant through weathered granites. The amount of consolidant was investigated by the weight change and, the measurement technique for the penetration depth was also investigated, demonstrating that the real penetration depth was very different with the surface traveling distance, which has been misconstrued to be the penetration depth. Therefore, it was suggested that the penetration depth of a model specimen should be measured from the cross-sectional face of the weathered stone, but not from the surface traveling distance [1]. 1. INTRODUCTION Many stone heritages, mostly made of granites and older than 1,000 years in Korea, have been continuously deteriorated with time, particularly by weathering including physical disintegration and chemical decomposition [2-4]. Consequently, mechanical properties of stone heritages become weaker upon weathering and stone heritages should be thus consolidated properly for preservation. There have been continuous efforts to develop new consolidants [5, 6]. Among stone consolidants, silicates are widely used and are commercially available. Thus, proper consolidants should be carefully selected depending on the physico-chemical properties of both the consolidants and the - 284 -
weathered stones in addition to the mineralogical and petrological properties of the stones. For a given consolidant and weathered stone, the penetration depth of the consolidant becomes critically important to give best consolidation effect. It is obvious that the deeper the penetration depth is, the better preservation effect can be obtained. In this paper, we investigated how to increase the penetration depth of a consolidant into the cavities of weathered stones [1]. 2. EXPERIMENTAL 2.1 Weight change Three different weathered granites from the site of Namsan, Kyungju, S. Korea were characterized by ultrasonic velocity and shore hardness. Two different consolidants of Wacker OH100 and 1T2G were used, where the 1T2G consolidant was a newly developed one by the current authors. The weathered side of a granites stone (15 x 15 x 10 mm 3 ) was brushed with each consolidant. Brushing was done several times and a gauze soaked with the consolidant was subsequently firmly attached onto the surface of the stone for 24 hrs at 20 and 50 RH. After 24 hrs, the granites were placed for 2 weeks in same condition and treated again in the same way. Weight change of the granite samples was measured continuously with time. 2.2 Penetration depth For the measurement of the penetration depth, the weathered side of a granite stone (30 x 30 x 35 mm 3 ) was contacted with a liquid consolidant containing a small amount (0.1 wt %) of a dye such as Red 336 in a beaker. The traveling distance of the dye was measured with naked eyes by two different methods: the traveling distance at the outer surface (the surface penetration distance) and that at cross-sectional or central part (the real penetration depth). [1] Experimentally, a brush was used to spread a consolidant over the surface of the weathered stones (30 x 30 x 35 mm 3 ). Brushing was done several times and a gauze soaked with the consolidant was subsequently firmly attached onto the surface of the stone. Additionally, the liquid consolidant was dropped at a rate of 1 droplet/min with a dropping funnel into the gauze to maintain the liquid state of the consolidant during long treatment time. The whole system for the consolidation treatment was covered by an air protection layer such as a polyethylene film to prevent from contact of the consolidant with water for solidification reaction on the surface. [1] - 285 -
3. RESULTS AND DISCUSSION The stones were characterized by various physico-chemical methods and summarized in Table 2. Depending on the ultrasonic velocity, the samples were categorized into the 2nd, 3rd and 4th grades or slightly (SW), moderately (MW) and highly weathered (HW) stones, respectively. Table 1. Weathering Grade of Namsan Granite samples [1] Weathering grade Ultrasonic velocity (m/s) Shore hardness SW (2 nd ) 4330-4680 21-35 MW (3 rd ) 2660-3370 32-46 HW (4 th ) 1808-1885 45-55 2.1 Weight change The weight change of the moderately weathered granites was measured as time goes. The weight of sample sharply increased duing being covered with gauze, but decreased continuously after gauze was removed. The increased weight of the granite During covered with gauze, the consolidant penetrate into the pore of the granite by capillary force of the consolidant. After 24 hrs, when the gauze was removed from the granite, the weight decreased gradually. Gauze promote the consolidant penetrate into the pores of granites without hardening at the surface of the granite as keeping the surface wet. After several days, weight of the granite was saturate at certain point, indicating that the sol-gel reaction was over. When weight change was not shown, 2 nd treatment was accomplished as the same method. The weight increasing by 2nd treatment was not as much as that of 1 st treatment. Increased weight of granite treated with Wacker OH100 was more than 1T2G 75%. - 286 -
Used Strengthener : Wacker OH100 Used Sample : MW1 50 Weight Change (mg) 45 40 35 30 25 20 15 10 5 0 Sample 8-1 (Untreated) Sample 8-2 (Once Treated) Sample 8-3 (Twice Treated) Sample 8-4 (Twice Treated) Initial Weight (mg) - (8-1) : 8875.2 - (8-2) : 6002.5 - (8-3) : 5740.0 - (8-4) : 5484.7 0 50 100 150 200 250 300 350 400 450 500 550 600 650 Time (hr) Used Strengthener : 1T2G 75wt%-DBLT Used Sample : MW1 Weight Change (mg) 35 30 25 20 15 10 5 0 0 50 100 150 200 250 300 350 400 450 500 550 600 650 Time (hr) Sample 10-1 (Untreated) Sample 10-2 (Once Treated) Sample 10-3 (Twice Treated) Sample 10-4 (Twice Treated) Initial Weight (mg) - (10-1) : 6466.2 - (10-2) : 6901.4 - (10-3) : 5336.9 - (10-4) : 4641.3 (a) (b) Figure 1. Weight change of sample stone treated by (a) Wacker OH100 and (b) 1T1G 75% (average surface area: 15 x 15 mm 2, method: brush & 24 hr gauze, and condition: 20 & 50% RH) 2.2 Penetration depth The real penetration depth of the Red 336 dye measured from the central part (or cross section) of the stone sample was very different with the surface traveling distance as listed in Table 2. The surface traveling distance was much longer than the real penetration depth. Surprisingly, two values were very different, suggesting that the real penetration depth of the model specimen should be measured through the cross section but not the surface traveling distance. In other words, the surface traveling distance has been misconstrued to be the real penetration depth and thus it should not be regarded as the real penetration depth. [1]. Table 2. Penetration depth and surface traveling distance of Wacker OH100 through moderately weathered granites [2]. Treatment time (hr) 1 12 24 48 Penetration depth (mm) 0 0 2 4 Surface traveling distance (mm) 7 17 > 37* > 37* *: the traveling distance was longer than the dimension of the specimen of 37-38 mm. The penetration depths for the MW stone were only 2 and 4 mm after 24 and 48 hrs treatments, respectively, whereas the surface traveling distance was longer than - 287 -
the dimension of the specimen of 37-38 mm within 24 hrs. For the HW granite, it was 7 mm upon 48 hrs consolidation treatment. The penetration depth was unexpectedly small. It was thus recommended that maintaining the liquid state of the silicate consolidant during the treatment time on the surface of the weathered stones is very important in achieving deeper penetration of consolidant for a given system of the consolidant and the weathered stone. [1] Therefore it is suggested the optimized method for deeper penetration: Maintaining liquid state at the surface of the weathered stones is the key factor for deeper penetration. We understand that when the viscosity of the consolidant on the surface of the weathered stone is increased by reacting with water, the penetration stops and thus the penetration depth is shallow. In order to maintain the liquid state on the surface, it is strongly recommended 1) to supply the liquid silicate solution continuously with an apparatus such as a dropping funnel and 2) to prevent or suppress the hydrolysis reaction by avoiding water contact with an air protection layer such as a polyethylene film [1]. 4. CONCLUSIONS A novel consolidation method to increase the penetration depth of silicate consolidants though weathered granites was suggested. In order to achieve the deep penetration of a consolidant through cavities of weathered stones, it is strongly recommended 1) to supply the liquid silicate continuously with an apparatus such as a dropping funnel, and 2) to prevent or suppress the hydrolysis reaction by avoiding water contact with an air protection layer such as a polyethylene film. It was also suggested that the experimental penetration depth should be measured from the cross-sectional face of the weathered stone, but not from the surface traveling distance. [1] ACKNOWLEDGEMENTS The financial support from the National Research Institute of Cultural Heritages of Korea is gratefully acknowledged. REFERENCES 1. J. H. Lee, S. J. Kim, Y. S. Kang, U. Y. Kim, J. J. Kim, J. Won and S. D. Kim, The Proceedings of the 11th International Congress on Deterioration and - 288 -
Conservation of Stone, Torun, Poland, 2008 2. G. Robinson and M..C. Baker, Wind-driven rain and buildings, Technical paper No. 445 of the Division of Building Research, National Research Council of Canada, Ottawa, July 1975 3. C. A. Price, Stone Conservation, J. Paul Getty Trust, 1996. 4. B. Fitzner, Evaluation and documentation of stone damage on monuments, International Symposium of Stone Conservation, Seoul, Korea, May 29, 2007. 5. M. J. Mosquera, D. M. de los Santos, and A. Montes, Producing new stone consolidants for the conservation of monumental stones, Materials Research Society Symposium Proceedings 852, 2005, art. no. OO6.4, pp. 81-87 6. M. J. Mosquera, D. M. de los Santos, A. Montes, and L. Valdez-Castro, New Nanomaterials for Consolidating Stone, Langmuir, 2008, 24, 2772-2778 - 289 -