The objective of this study is to evaluate the sulfuric acid resistance of biomimetic coating mortars based on glycocalyx substance generated around the bacteria cell to protect the substrate of concrete. Rhodobacter capsulatus was isolated as a bacteria strain, and expanded vermiculate or super absorbent polymer, employed for immobilizing the bacteria, were used at 30 % volume for replacement of fine aggregates in coating mortars. The coating mortars using expanded vermiculate containing bacterial agents exhibited better performance than the other mortars with respect to the following: the 28-day compressive strength and population of viable bacteria were 40.7 MPa and 4.6×106 cell/mL, respectively; the variations of compressive strength and mass measured in specimens immersed in 5 % sulfuric acid solution were less than 2 %; and the gypsum production due to the hydrate chemical action against sulfuric acid was 17 % lower than that of the mortar without bacteria. As a result, the proposed biomimetic coating mortars have great potential as protective materials for blocking deterioration of concrete.
이 연구의 목적은 콘크리트 구조체 보호를 위한 박테리아의 글라이코 캘릭스 기반의 생태학적 코팅 모르타르의 내황산성 평가이다. 글라이코 캘릭스를 형성하는 균주로서 Rhodobacter capsulatus가 선별되었고, 박테리아 고정화 재료로서 팽창질석 및 고 흡수성 수지가 잔골재 부피 대비 30 % 치환되었다. 박테리아를 고정한 팽창질석을 혼입한 코팅 모르타르는 다음과 같은 측면에서 다른 시험체에 비해 우수한 성능을 보였다. 재령 28일 압축강도 및 박테리아 생균수는 각각 40.7 MPa 및 4.6 × 106 cell/mL이며, 황산 5 % 수용액 침지 후 재령 28일에서의 압축강도 변화 및 질량 변화율은 2 % 이하이며, 석고의 생성량도 박테리아 무혼입 시험체 대비 17 % 낮았다. 결과적으로 제시된 생체 모방형 코팅 모르타르는 콘크리트 열화요인 차단을 위한 보호재로서 적용 가능성이 높다고 판단된다.
- Bae, S. H., Park, J. I., and Lee, K. M. (2010) Influence of Mineral Admixtures on the Resistance to Sulfuric Acid and Sulfate Attack in Concrete. Journal of the Korea Concrete Institute 22(2), 219-228. (In Korean)
- Beak, C. W., Kim, H. S., Choi, S. W., Jo, H. T., and Ryu, D. H. (2015) Durability Assessment of High Strength Concrete with High Volume Mineral Admixture. Journal of the Korea Concrete Institute 27(6), 641-649. (In Korean)
- Choi, S. H., Lee, K. J., Hong, S. Y., and Lee, S. G. (1988) Effect of Salts on the Hydration of ɑ-Calcium Sulfate Hemihydrate. Journal of the Korean Ceramic Society 25(5), 449-454. (In Korean)
- Clifton, J. R. and Knab, L. I. (1989) Service Life of Concrete. Washington DC: National Bureau of Standards. No. NISTIR 89-4086.
- Engbrecht, D. and Hirschfeld, D. A. (2016) Thermal Analysis of Calcium Sulfate Dihydrate Sources Used to Manufacture Gypsum Wallboard. Thermochimica Acta 639, 173-185.
- Hong, S. R., Kim, H. S., Kwak, E. G., Park, S. G., and Kim, J. M. (2011) Characteristics of Recycled Fine Aggregate by Sodium Carbonated Water. Journal of the Korean Recycled Construction Resources Institute 14, 97-106. (In Korean)
- Lee, K. H. and Yang, K. H. (2016) Evaluation of pH and Compressive Strength Development of Alpha-Calcium Sulfate Hemihydrate-based Binder. Journal of the Korea Institute of Building Construction 16(1), 59-65.
- Monteny, J., Vincke, E., Beeldens, A., Taerwe, L., Van Gemert, D., and Verstraete, W., (2000) Chemical, Microbiological, and in Situ Test Methods for Biogenic Sulfuric Acid Corrosion of Concrete. Cement and Concrete Research 30(4), 623-634.
- Oh, K. J., Ryu, K. J., Bae, T. H., Kim, D. H., and Bae, J. J. (2006) Inspection of Chemical Attacked Sewage Concrete Structures. Magazine of the Korea Concrete Institute 18(2), 22-26. (In Korean)
- Park, J. I., Bae, S. H., Lee, K. M., and Ha, J. D. (2011) Resistance against Chloride Ion Penetration of Concrete Subjected to Sulfate Attack. Journal of Korean Society of Urban Environment 11(2), 145-152. (In Korean)
- Ramachandran, S. K., Ramakrishnan, V., and Bang, S. S. (2001) Remediation of Concrete using Micro-Organisms. ACI Materials Journal 98, 3-9.
- Wang, J. Y., Snoeck, D., Van Vlierberghe, S., Verstraete, W., and De belie, N. (2014) Application of Hydrogel Encapsulated Carbonate Precipitating Bacteria for Approaching a Realistic Self-Healing in Concrete. Construction and Building Materials 68, 110-119.
- Yang, K. H., Yoon, H. S., and Lee, S. S. (2016) Sulfate Resistance Coating Technology for Concrete Drain Pipe using Bacteria Slime. Magazine of the Korea Concrete Institute 28(3), 18-22. (In Korean)
- Yang, K. H., Yoon, H. S., and Lee, S. S. (2018) Feasibility Tests toward the Development of Protective Biological Coating Mortars. Construction and Building Materials 181, 1-11.
- Yoon, H. S., Jung, S. B., Yang, K. H., Lee, S. S. and Lee, J. Y. (2016) Compressive Strength and Ecological Characteristics of Mortars Using Expanded Vermiculite Absorbing Bacteria. Journal of the Korean Recycled Construction Resources Institute 4(2), 165-171. (In Korean)
- Yoon, H. S., Yang, K. H., and Lee, S. S. (2018) Bacteria Mobilizing Approach for Developing Biomimic Coating Materials for Concrete Protection. Journal of the Korea Concrete Institute 30(2) 147-155. (In Korean)
- Publisher :Korea Concrete Institute
- Publisher(Ko) :한국콘크리트학회
- Journal Title :Journal of the Korea Concrete Institute
- Journal Title(Ko) :콘크리트학회 논문집
- Volume : 31
- No :1
- Pages :61-68