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China Vacation

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Title: China Vacation


1
SUSTAINABLE CONCRETE TECHNOLOGY CHALLENGE AND
OPPORTUNITY
Dr. Tony C. Liu Dr. Jenn-Chuan
Chern Visiting Research Fellow
Distinguished Professor
National Taiwan University, Taiwan, ROC
2
Presentation Outline
  • Challenges facing concrete industry
  • Sustainable Concrete Technologies
  • Improved cement manufacturing technology
  • Use of supplementary cementing materials
  • Recycle and reuse of concrete
  • Enhancement of service life
  • Research and use of emerging technologies
  • Conclusions

3
Low Material Cost Low Construction Cost Low
Maintenance Cost Good Durability
4
(No Transcript)
5
Concrete Production in Taiwan (2007)
  • 65 million m3
  • 150 million Tons
  • 1 of total world concrete production
  • 0.3 of world population
  • 6.5 tons/person

6
Challenges Facing Concrete Industry (1/2)
  • Population will continue to increase
  • 6.7 billion in 2008
  • 10 billion in 2050
  • Most of the populations are in Asian region
  • Infrastructure needs will grow
  • Provide needs of the increasing population
  • Aging and deteriorating infrastructure
  • Repair and rehabilitation needs are increasing

7
Challenges Facing Concrete Industry (2/2)
  • Natural resources and non-renewal energy are
    becoming scarce
  • 3 billion tons of limestone
  • 13 billion tons of aggregates
  • 64 billion GJ of energy (fossil fuel and
    electricity)
  • Urgent need to reduce greenhouse gas emission
    to combat global warming
  • 7 of the total world CO2 emissions from cement
    production
  • 11 of the greenhouse gas emissions from life
    cycle of concrete and concrete structures

8
How Can We, the Concrete Industry, Meet the
Challenges?
  • We need to adopt sustainable concrete
    technologies to meet the infrastructure needs, to
    save energy, to reduce CO2 emissions, and to
    protect environment

9
Sustainable Concrete Technologies
  • Reduce environmental impacts of cement production
  • Greater use of supplementary cementing materials
  • Recycle and reuse of concrete
  • Enhancement of service life of concrete
    structures
  • Research and use of emerging technologies

10
Reduce Environmental Impacts of Cement Production
11
Asias Increasing Share of Consumption of Cement
From Prof. Ouchi
12
Consumption of Cement in Asian Regions
From Prof. Ouchi
13
Use of Cement, Slag, and Fly Ash in Taiwan (2007)
  • Cement
  • 13.5 million tons
  • GGBF Slag
  • 5 million tons
  • Usage Rate 100
  • Fly Ash
  • 4 million tons
  • Usage Rate 70

14
Environmental Effects of Cement Production
  • Emission of CO2
  • Each ton of cement contributes one ton of CO2
  • High energy use (fossil fuel and electricity)
  • 4GJ of energy per ton of finished cement
  • Use of natural raw materials
  • Each ton of cement requires 1.5 tons of limestone
  • How can we reduce the
    environmental impacts of
  • cement production?

15
Reduce Environmental Impacts of Cement Production
  • Placing wet production facilities with modern
    dry-processing plants
  • Greater use of alternative fuels (petroleum coke,
    used tires, rubber, paper waste, waste oil, etc)
  • Greater use of recycled mineral by-products as
    raw materials in the cement kiln.
  • Decreasing electricity consumption during milling
    of cement by modernization of machinery.

16
Greater Use of Supplementary Cementing Materials
(SCM)
17
SCM The most Sustainable Construction Materials
  • SCM Fly Ash, GGBF Slag, Silica Fume
  • Recovers industrial byproduct
  • Avoids disposal
  • Reduces portland cement
  • Decreased use of energy
  • Decreased greenhouse
  • gas emission
  • Decreased use of
  • virgin materials
  • Improves durability

18
Fly Ash in Concrete
  • About 600 million tons annually world-wide
    (10-15 used in concrete)
  • Better workability
  • Reduce temperature rise
  • Improve durability
  • High-performance, high-volume fly ash concrete

19
High-Performance, High-Volume Fly Ash Concrete
  • Fly ash replacement gt50
  • Low water content lt130 kg/m3
  • Cement content lt200 kg/m3
  • W/CM 0.30 or less
  • Use HRWRA
  • Excellent long-term mechanical and durability
    properties

20
Ground-Granulated Blast-Furnace Slag
  • World production of slag 100 million tons
  • Granulated form 25 million tons
  • Utilization rate as a cementitious materials has
    increased in recent years and this trend is
    expected to continue
  • Blended slag cement (50 slag content)

21
Use of GGBF Slag in Taiwan
  • 5 million tons of GGBF slag were used in concrete
    mixtures in 2007
  • High Volume slag concrete (55 to 45 of slag
    replacement rate) was commonly used in Taiwan for
    applications where high or moderate sulfate
    resistance is required

22
High Volume Slag Concrete
  • High volume GGBF slag in superplasticized
    concrete
  • Excellent mechanical properties
  • Good resistance to carbonation
  • Good sulfate resistance
  • Good resistance to penetration of organic liquids
  • Good freezing and thawing resistance (without air
    entrainment)
  • Good salt scaling resistance

23
Silica Fume
Condenses from furnace gases
20,000 x
  • By-product of silicon metal or ferrosilicon alloy
    production
  • Smooth, spherical, glassy particles
  • 0.1 to 0.15 micron, about 1/100
  • the size of cement particles
  • Worldwide production - 2 million tons

24
Applications of SF Concrete
  • Property-enhancing applications
  • Ultra High Strength Requirements
  • High Abrasion Resistance
  • Early-Age Strength Improvement
  • Corrosion Protection
  • Repair applications

1600 m3 of silica fume concrete was placed in 1983
25
Major Barriers Against the Use of Large
Quantities of SCM
  • Prescriptive-type of specifications and codes
  • Limit on the use of SCM
  • Minimum cement content
  • Strength requirement at early age (28 days rather
    than 56 days or longer)
  • Education and Technology Transfer

Need to develop performance-based specifications
and codes that will accelerate the rate of
utilization of SCM
26
Recycle and Reuse of Concrete
27
Construction Demolition (CD) Waste
  • 1 billion tons of CD waste (broken concrete,
    bricks, and stone) are generated annually
    worldwide
  • 10 million tons of CD waste generated annually
    in Taiwan

28
Use of Construction Demolition (CD) Waste
  • Used mainly for road base and sub-base materials
  • Also used as partial replacement of coarse
    aggregate for structural concrete
  • Increased attention in European countries, Japan,
    U.S., and Taiwan

29
Recycling Other Materials in Concrete
  • Foundry sand
  • Cupola slag from metal-casting industries
  • Glass
  • Wood ash from pulp mills
  • Sawmills
  • De-inking solids from paper-recycling companies

30
Future Outlooks for Recycling
  • Local natural aggregate sources are scarce
  • Suitable landfill sites are becoming scarce
  • Improvements in demolition, processing, and
    handling technologies will improve the quality
    and decrease the cost of recycled concrete
    aggregates
  • Availability of design and construction
    specifications for recycled concrete

31
Enhancement of Service Life
32
Existing Infrastructure Conditions
  • Significant parts of the world infrastructure are
    aging and deteriorating
  • Overall grades of infrastructure report cards
  • USA (ASCE) D
  • UK (ICE) D
  • Australian (EA) C
  • S. Africa (SAICE) D

33
Causes of Premature Deterioration of Concrete
Structures
  • Electro-chemical
  • Corrosion of embedded metals
  • Physical
  • Freezing and thawing
  • Erosion
  • Shrinkage
  • Thermal stresses
  • Chemical
  • Acid attack
  • Sulfate attack
  • ASR

Poor-quality concrete will deteriorate
prematurely and will require costly repairs and
waste of natural resources and energy
34
Durable Concrete Structures
  • Large savings in natural resources and energy can
    result if the concrete structures are much more
    durable
  • Extending service life of the existing
    infrastructure instead of removal and rebuild
    requires less natural resources and energy

Use life-cycle cost approach by seeking better
and durable concrete structures rather than lower
initial cost
35
Research and Use of Emerging Technologies
  • Emerging technologies that have the potential to
    significantly contribute to sustainable concrete
    industry
  • Repair and Rehabilitation technology
  • Ultra-high strength concrete
  • Nanotechnology

36
Repair and Rehabilitation Technology
  • Evaluation Tools and Modeling Technologies
  • New and improved NDT
  • High tech long-term health monitoring systems
  • Performance-based durability design
  • New Repair Materials and Systems
  • Durability of repair systems
  • Smart materials and systems
  • Field Process Technologies
  • Improved Management Systems for Existing
    Infrastructure

37
Ultra-high Strength Concrete
  • Unique combination of properties
  • Superior strengths
  • Good ductility
  • Good durability
  • Lighter and durability structures
  • Requiring less raw materials
  • Requiring less energy
  • Generating fewer CO2 emissions

38
Nanotechnology in Concrete
  • Nano-catalysts to reduce clinkering temperature
    in cement production
  • Silicon dioxide nano-particles (nanosilica) for
    ultra-high strength concrete
  • Incorporation of carbon nano-tubes into cement
    matrix would result in stronger, ductile, more
    energy absorbing concrete
  • Eco-binders (MgO, geopolymers, etc) modified by
    nano-particles with substantially reduced volume
    of portland cement

39
Governments Sustainable Development Policy for
Infrastructure
  • Taiwan Public Construction Commission prepared
    and the Executive Yuan approved a white paper and
    action plan on Sustainable Public Infrastructure
    - Energy Saving and Carbon Reduction in November
    2008
  • The SD policy for infrastructure is being
    implemented in Taiwan

40
Conclusions
  • We, the concrete industry, need to adopt the
    following sustainable concrete technology to meet
    the infrastructure needs and protect the
    environment
  • Use more supplementary cementing materials
  • Recycle and reuse of concrete
  • Use life-cycle cost approach to seek better and
    durable concrete structures
  • Research and use of emerging technologies (e.g.,
    repair and rehabilitation technology to extend
    service life of infrastructure)

41
Thank You!
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