시멘트계 재료의 기체 투기계수 해석 및 투수계수와의 상관성 연구 = Modeling of Gas Permeability Coefficient for Cementitious Materials with Relation to Water Permeability Coefficient

다국어 초록 (Multilingual Abstract)

Permeability can not be expressed as a function of porosity alone, it depends on the porosity, pore size and distribution, and tortuosityof pore channels in concrete. There has been considerable interest in the relationship between microstructure and transport incementitious materials, however, it is very rare to deal with the theoretical study on gas permeability coefficient in connection withcarbonation of concrete and the effect of volumetric fraction of cement paste or aggregate on the permeability coefficient. The majorityof these researches have not dealt with this issue combined with carbonation of concrete, although carbonation can significantly impacton the permeability coefficient of concrete. In this study, fundamental approach to compute gas permeability of (non)carbonatedconcrete is suggested. For several compositions of cement pastes, the gas permeability coefficient was calculated with the analyticalformulation, followed by a microstructure-based model. For carbonated concrete, reduced porosity was calculated and this was usedfor calculating the gas permeability coefficeint. As the result of calculation of gas permeability for carbonated concrete, carbonationleaded to the significant reduction of gas permeability coefficient and this was obvious for concrete with high w/c ratio. Meanwhile,the relationship between gas permeability and water permeability has a linear function for cement paste based on Klinkenberg effect,however, which is not effective for concrete. For the evidence of the modeling, YOON’s test was accomplished and these results werecompared to each other.

국문 초록 (Abstract)

투기계수는 콘크리트의 공극뿐만 아니라 공극크기, 공극분포, 공극간의 굴곡특성에 의해서도 영향을 받는다. 투기계수는 시멘트 페이스트의 미세구조에 의해 지배되는데, 시멘트 페이스트 및 골재 각각이 콘크리트의 투기성능에 미치는 영향을 다룬 연구는 드물다. 더우기, 탄산화가 투기계수에 큰 영향을 미칠 수 있음에도 불구하고, 탄산화된 콘크리트에 대한 투기계수를 다룬 연구는 더욱 드문 실정이다. 본 연구의 목적은 탄산화및 비탄산화된 콘크리트의 투기계수를 추정할 수 있는 기초적 접근방법을 개발하는 것이다. 본 연구에서는 미세구조 모델 및 시멘트의 경화특성을 기초로 투기계수를 산정할 수 있는 해석적 기법이 제안되었다. 탄산화된 콘크리트에서 감소된 공극량이 계산되었으며 이는 투기계수의 산정에 이용하여 탄산화된 콘크리트의 투기계수를 계산하였다. 높은 물-시멘트비를 갖는 콘크리트는 탄산화로 인하여 투기계수의 감소가 더욱 뚜렷한 것을 확인되었다. 한편, 시멘트 페이스트에서 투기계수와 투수계수는 Klinkenberg

참고문헌 (Reference)

1 윤인석, "탄산화 및 비탄산화된 콘크리트의 투수계수의 해석 기법 개발" 한국콘크리트학회 21 (21): 255-264, 2009

2 윤인석, "중성화의 영향을 고려한 콘크리트의 염소이온 확산계수 산정에 대한 해석적 기법 연구" 대한토목학회 27 (27): 617-625, 2007

3 Nokken, M. R., "Using pore parameters to estimate permeability or conductivity of concrete" 41 (41): 1-16, 2008

4 Klinkenberg, L. J., "The Permeability of Porous Media to Liquids and Gases" American Petroleum Institute 1941

5 Koenders, E. A. B., "Simulation of Volume Changes in Hardening Cement-Based Materials" Delft University of Technology 1997

6 Van Breugel, K., "Simulation of Hydration and Formation of Structures in Hardening Cement-Based Materials" Delft University of Technology 1991

7 FORGE, "Results of the Tests on Concrete" 2011

8 Dias, W. P. S., "Reduction of concrete sorptivity with age through carbonation" 30 : 1255-1261, 2000

9 Katz, A. J., "Quantitative prediction of permeability in porous rock" 34 (34): 8179-8181, 1986

10 Papadakis, V. G., "Physical and chemical characteristics affecting the durability of concrete" 8 (8): 186-196, 1991

11 RILEM Report 12, "Peromance Criteria for Concrete Durability" E & FN Spon 24-25, 1997

12 Picandet, V., "Permeability measurement of fresh cement paste" 41 (41): 330-338, 2011

13 Peter, A. C., "Permeability and pore volume of carbonated concrete" 378-382, 1999

14 Hirsch, T. J., "Modulus of elasticity of concrete affected by elastic moduli of cement paste matrix and aggregate" 59-12 : 427-451, 1962

15 Persoff, P., "Hydrologic Characterization of Reservoir Metagraywacke from Shallow and Deep Levels of the Geysers Vapor-dominated Geothermal System, California, USA" 30 : 169-192, 2001

16 Furbish, D. J., "Fluid Physics in Geology; An Introduction to Fluid Motions on Earth’s Surface and within its Crust" Oxford University Press 1997

17 Neithalath, N., "Enhanced porosity of concrete: Permeability, Electrical Conductivity and Acoustic Peorformance" 2003

18 Ahmad, S., "Effect of the key mixture parameters on tortuosity and permeability of concrete" 10 : 86-94, 2012

19 Ngala, V. T., "Effect of carbonation on pore structure and diffusion properties of hydrated cement pastes" 27 (27): 995-1007, 1997

20 Bear, J., "Dynamics of Fluids in Porous Media" American Elsevier Publishing Co. Ltd. 1972

21 Verbeck, G. J., "Corrosion of metals in concrete" ACI SP49, Special Publication 21-28, 1975

22 Samson, E., "Calculation of inonic diffusion coefficients on the basis of migration test results" 36 (36): 156-165, 2003

23 Tang, L., "Astudy on the quantitative relationship between permeability and pore size distribution of hardened cement pastes" 22 (22): 541-550, 1992