Modeling for Frost Damage and Standard for Life Cycle Management

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1 Modeling for Frost Damage and Standard for Life Cycle Management Introduction of JST Program UEDA Tamon Hokkaido University JST Open Seminar, Qingdao, 6 March 2012

2 1 Introduction This paper introduces 1. International cooperative project: Life Cycle Prediction and Management of Concrete Structures The Asia-Africa S & T Strategic Cooperation Promotion Program of Special Coordination Funds for Science and Technology of Japan (JST) s Ministry of Education, Culture, Sports, Science and Technology (MEXT) 2. A part of the project: Modeling for Frost Damage A technology for life cycle prediction

3 2 Introduction Life Cycle Management (LCM) makes it possible to effectively use resources and energy, reduce the effects on the environment, and optimize the economic burden in the society is important in Asia where two-thirds of infrastructures in the world are being constructed

4 3 Outline of Project Team Member Institution Yonsei University, Korea Qingdao Technological University, China Zhejiang University Dalian University of Technology, China Chulalongkorn University, Thailand Assiut University, Egypt Hokkaido University, Japan Kagoshima University, Japan Muroran Institute of Technology, Japan Public Works Research Institute, Japan Port and Airport Research Institute, Japan Hokkaido Northern Regional Building Research Institute, Japan Member name Prof SONG Ha-Won (diseased), and Dr ANN Ki-Yong Prof Folker H WITTMANN Prof JIN Wei-lian Dr WANG Li-cheng Dr Boonchai STITMANNAITHUM Dr Ahmed Sabry Abdel Hamid FARGHALY Prof UEDA Tamon*, Prof YOKOTA Hiroshi, Prof SUGIYAMA Takafumi, Dr SATO Yasuhiko, Dr HASHIMOTO Katsufumi, and Dr ZHANG Da-wei Prof TAKEWAKA Koji and Dr YAMAGUCHI Toshinobu Prof HAMA Yukio and Dr KISHIMOTO Yoshihiko Dr TAGUCHI Fumio, Mr HAYASHIDA Hiroshi, Dr ENDO Hirotake and Dr YOSHIDA Susumu Dr KATO Ema Dr KATSURA Osamu, Ms TANIGUCHI Madoka and Dr IBA Chiemi

5 Outline of Project 4

6 5 Outline Research Contents FY Deterioration assessment of existing structures Integration of environmental/social impact evaluation and durability design FY Proposal of national and international standards for LCM Clarification of various deterioration mechanism FY2011 Life cycle prediction of structures Interventions against deterioration of structures Durability design and maintenance management system FY2011

7 Outline of Project - Process for Development of International Standards 6 Japan (JCI) Korea (KCI) Thailand (TCA) National Standards China JST Project Life Cycle Prediction and Management of Concrete Structures Asian Concrete Federation ISO/TC71/SC7 Maintenance and Repair of Concrete Structures International Standards Asian Concrete Model Code ISO Standard

8 Outline - Project Outcome 1. Systemization of Prediction Technology and Life Cycle Management Deterioration Mechanism by Salt Attack and Performance Prediction Deterioration Mechanism by Frost Attack and Performance Prediction Deterioration Mechanism under Combined Effects and Performance Prediction Durability Design with Consideration of Combined Deterioration Strengthening by Overlaying and External Bonding as Intervention against Deterioration 2. Proposal of national and international standards for LCM 7

9 Modeling for Frost Damage Outcome as a part of Deterioration Mechanism by Frost Attack and Performance Prediction 8 Deformation model of mortar in meso scale under temperature and moisture variation [Ueda in this project] [5] Model of mortar-aggregate interface in meso scale under temperature and moisture variation Simulation of frost damage in concrete [Ueda in this project] [4] Simulation of property of frost-damaged concrete [1][2] Material analysis Model of frost damaged concrete [3] Prediction of structural performance of member with frost damage Structural analysis

10 Deformation due to Freeze Thaw Cycles Modeling for Frost Damage 9 Modeling of deformation in meso scale Causing cracks and plastic deformation in concrete Causing degradation of mechanical and durability properties σ c Modeling of frost-damaged concrete in macro scale ε c Prediction of structural performance of concrete with frost damage

11 Modeling for Frost Damage 10 Strain (µ) FTC 1st 2nd 3rd 4th 5th Time (minutes) (a) Dry mortar Strains (µ) FTC 1st 2nd 3rd 4th 5th Time (minutes) (b)100% sat. mortar with thermal strains Strains (µ) FTC 1st 2nd 3rd 4th 5th Time (minutes) (c) 100% saturated mortar less thermal strains Ice formation which causes water to expand Water filled pores (d) Representation of interconnected pores in mortar: Ice formation causing large expansion and water filled pores

12 Modeling for Frost Damage 11 Matsumoto Model Heat and Moisture Equations for Three Phase from Dr. Matsumoto ψ μ ρl = μ t T Cρ = t μ = H li ( μ) { } ( λ + λ T) μ {( ) } { λ+ Rλ T + Rλ ( μ) } log e Tg T T 0 μg T ρ iψ i t + H li ρψ l t i Ψ i - Ice content Ψ - Moisture content T - Temperature Strains during FTC ε = α ψ i ε T =α T d i i Expansion strains Thermal Strains

13 ε ε + ε + ε Modeling for Frost Damage 12 = Deformation - a combination of three strain i s t components. ε ε ε i t s =α i s Ψ ( Ψ Ψ ) = α - =α T T t i w ic Shrinkage strains Expansion strains Thermal strains Ψ w Unfrozen water content Ice content Ψ i Ψ ic Minimum ice content when deformation start to depend on ice formation T Temperature difference α s, α i, and α t material constants and values

14 Modeling for Frost Damage 13 Material Constants and Values Value representing the contribution of unfrozen water content to the shrinkage. α s f ( Ψ ) = lnψ = w w Material constant during freezing Shrinkage value α i = 2116 x 10-6 Freezing coefficient Linear expansion/contraction of the material. α t = x 10-6 Linear expansion coefficient Calculation of temperature (T), moisture (Ψ) and ice content (Ψ i ) by heat and moisture balance for three phases Calculation of total strain by the proposed model ε = ε + ε + ε i s t

15 Modeling for Frost Damage 14 Analysis of Deformational Behavior of Mortar: Partially Saturated (85% RH) Specimen Location of Analysis Temperature change and constant moisture supply Mortar Model Temperature and moisture insulated Size:100 mm x 100 mm Initial moisture condition: 85% RH Initial temperature: 20 ºC Temperature (ºC) Time (hour) Temperature history initiated on top side

16 Analysis Results Volume % (m 3 /m 3 ) Ice content (Ψi) Moisture content (Ψ) Time (hour) Modeling for Frost Damage 15 a) Ice content and moisture content with time Temperature (ºC) Strain (µ) Temperature (ºC) Strain (µ) Time (hour) Time (hour) b) Deformation with thermal strains c) Deformation without thermal strains

17 Latest results Modeling for Frost Damage Initially expansion to contraction later 16 Specimen 50% w/c (754kg/m 3 ) 50% w/c (1090kg/m 3 ) 70% w/c (1090kg/m 3 ) Dry Specimen (Undamaged) (με) FTC Damaged - Thermal Strain (με) Difference (με) FTC Damaged Dry Specimen CalculatedThermal expansion (undamaged) (10-6 /ºC) Larger thermal coefficient after FTC CalculatedThermal expansion (damaged) (10-6 /ºC)

18 Concluding Remarks Long life of infrastructure, which needs massive resources and energy, is vital for sustainability especially in Asia, where two thirds of the world infrastructures is being constructed. In this project life cycle prediction and rehabilitation methods for concrete structures under environmental actions (such as temperature/moisture and corrosive substance) causing deterioration are presented with consideration of the local conditions of material quality and climate in Asia and Africa. Then, the international standards for life cycle management (LCM) of concrete structures will be prepared by the Asian and African international team in ISO where European and American countries are dominant. 17

19 18 THANK YOU FOR ATTENTION