concrete and sustainability - petra christian...
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Concrete and Sustainability
Koji SakaiProfessor of Kagawa University
Chair of ISO/TC71/SC8, fib SAG 8, JCI Sustainability Comm., ACF SF
HAKI‐ACF JOINT SEMINAR18 September 2013,
Petra Christian University, Surabaya, Indonesia
From the Earth’s Birth to Present The Earth is 4.6 billion year old. Life has evolved for 4 billion years. Origin of modern humans was born 100,000 years ago Agricultural revolution occurred 10 thousand years ago. Industrial revolution occurred 250 years ago. Modern cement was invented in 1824. Concept “sustainable development” was defined in 1987.
Our Common Future (World Comm. on Env. and Dev.)“Sustainable development is development that meets the needs of the
present without compromising the ability of future generations to meet their own needs.” Kyoto protocol (COP3) was adopted in 1997 and entered into
force in 2005. UN Conference on Sustainable development (Rio+20) is held
on June 2012.
What was happening in the Earth’s climate since its birth? (to be Cont’d)
The Earth repeatedly experienced climate warming and cooling due to:(1) change in gases in atmosphere:
‐major volcanic activity‐ photosynthesis‐ asteroid collision
(2) change of inclination of the Earth’s axisof rotation and eccentricity of its orbit
What was happening in the Earth’s climate since its birth? (Cont’d)
Carbon cycling on a geological time scale ‐ from CO2 gas to carbon fixation
Rapid increase of atmospheric CO2 levels‐ acceleration of global carboncycling by humankind
Global warming by green house gases ?
Data of Planets in the Solar System
Sun
Mercury Venus Earth Mars
Temperature(℃)
Max. ‐ 427 500 60 20
Min. ‐ ‐183 ‐45 ‐89 ‐140
Mean 5505 167 464 15 ‐63
CO2 (%) ‐ ‐ 96 0.038 95(thin atom.)
Greenhouse Gas Effect on Climateof Planets
Mercury (nearest to Sun ): 167 ℃ (no CO2) Venus: 464 ℃ (high CO2 : 96%:) Earth: 15 ℃ (0.038% CO2)Mars: ‐ 63 ℃ (very thin CO2)
“Global greenhouse effect due to increasing CO2 is so evident. Of course, we do not know exactly how much it will affect the Earth in the future, depending on GHG increase. Then, do we ignore it?”
Natures of Concrete Industry (1)
Essentially local industry“Concrete structures are built by local people using local materials.”
Component materials of concreteaggregate, cement, water, others“Concrete is made from the most abundantsubstances on the Earth.”
Natures of Concrete Industry (2)
This is the main reason why its productionhas been able to expand to respond togrowing construction demand.
Concrete is the second most consumed substance on Earth after water (more than20 billion tons).
Natures of Concrete Industry (3)
Contemporary society can not exist withoutconcrete.
Development of a nation is directly correlated to its consumption of concrete,i.e. the increase of construction investment.
World Cement and Steel Productionsince 1950
0
200
400
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1000
1200
1400
1600
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200019
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1955
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1965
1970
1975
1980
1985
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2005
2009
2015
2020
2025
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2045
2050
(%)
cement production
steel production
population
GDP per capita
1960=100%
(1960=316.5 million tons)
(1960=346.4 million tons)
(1960=3,023.4 million)
(1960=446US$)
0
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0 5000 10000 15000 20000 25000 30000 35000 40000 45000 50000
2006
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FranceGermanyJapanUnited KingdomUnited StatesChinaIndiaVietnamJapan*
GDP / capita (US$)
Con
stru
ctio
n in
vest
men
t / c
apita
(US$
)
Per Capita GDP and Construction Investment in Major Countries
* Japan in 2007 and 2008 calculate from construction investment of Research Institute of Construction and Economy. ** China/India/Vietnam: IMF(2001-2008), United States: OECD(1977-2006), other: OECD(1970-2006)
Source: OECD “Stat Extracts”, IMF “World Economic Outlook Database”
What are the Problems on Concrete from Sustainability’s Point of View?
Inadequate safety and reliability of concrete structures to unforeseen external forceEnormous consumption of natural resourcesGeneration of a large amount of CO2 incement/steel productions and constructionworks
Safety and Reliability
Our design standards and specifications on safety have been improved based on manyexperiences from serious disaster by forexample severe earthquakes.
However, we have still the problems that we can not foresee. It is reasonable to think that we can not control the movement of the Earth.
JAPAN DISASTER 3.11
What was the Japan Disaster 3.11?
Triple disasters(1) Earthquake (M9.0)(2) Tsunami(3) Radioactive pollution due to the hydrogen
explosion of nuclear power plant
Death and missing: approx. 20,000Destruction of houses: approx. 170,000
(if minor damage included, approx. 900,000)Evacuees: approx. 320,000 (as of November 17)Nuclear power plants (54): nothing under operation
Tsunami
Damage of railway viaduct columns
Damage of power pole in railway
Damage of bridge shoe
Damage of port and breakwater
References JSCE Concrete Committee Port and Airport Research Institute Structural Engineering Center, JR‐EAST http://japanese.joins.com/photo/337/8/71337.html http://mainichi.jp/select/weathernews/news/20110314k0000m040.html http://suiseisekisuisui.blog107.fc2.com/blog‐entry‐1679.html http://www.sankeibiz.jp/compliance/news/110324/cpd1103240501.html http://suiseisekisuisui.blog107.fc2.com/blog‐entry‐1679.html http://blogs.yahoo.co.jp/aiuti27go3/24055474.html
Japan Disaster
The earthquake destroyed social and economic infrastructures.The earthquake caused tsunami that also destroyed the infrastructures and houses/buildings.The tsunami destroyed the electric power facilities, that led to interruption of cooling water supply, the hydrogen explosion in NPP occurred and radioactive substances scattered over the region.
Lessons from Japan Disaster
Without robust infrastructures and houses/buildings, human society has no chance of sustainability:(1) Environmental aspects(2) Economic aspects(3) Social aspects
Environmental Aspects
Crustal deformation changed natural environment. (Nature destroyed nature!)Huge amounts of rubble were generated.Huge amounts of resources and energy are necessary to rebuild infrastructures and houses/buildings.Radioactive contamination occurred in some regions.
Economic Aspects
The economic activity in the regions collapsed. A cluster of plants producing automotive and electronic parts that served the world stopped.
The overseas transfer of manufacturing plants will be accelerated. Local economy will collapse.
Many people lost their job and therefore income.Huge amounts of investment is necessary to reconstruct the region. 20 trillion yen?
Cleaning up radioactive contamination (cesium etc.) is needed.
Social Aspects
There were 20,000 victims.Many people lost their homes.Long‐term evacuation of the local population is expected due to radioactive contamination.Many jobs were lost.
Essence of Sustainability
The destruction of social infrastructure and facilities exerts a lethal negative impact on economic and social activity. In other words, the basis of sustainability collapsed.
On the other hand, the simple expansion of economic activity using the infrastructures is not desirable from a sustainability’s perspective.
The enhancement in resource and energy efficiency to facilitate economic expansion and safety society is our ultimate goal, which is the essence of sustainability.
Consumption of Natural Resourcesin Concrete Sector
Aggregate: 11 billion tons (assuming 15 billion tons concrete production, that is conservative number)
Limestone:3 billion tons (assuming 3 billion tons cement production)
Clay: 540 million tons (assuming 3 billion cement production)
Water: 1.5 billion tons
Total for resources use in concrete: more than 16 billion tons (if doubled in the future? Huge!)
Negative Impacts in Concrete and Steel Productions
Enormity of resources usedGeneration of large amounts of CO2, global warming gas
However, no material can replace concrete and steel. Wood, for instance, has an extremely limited range of use for living and activities of 7 billion people. If wood is used instead of concrete and steel, other environmental problems, including land use, will occur.
CO2 Emission Sources in Concrete Sector
Material manufacture (cement, reinforcing bars, aggregates, water, admixtures)Concrete manufactureExecutionRepair and strengthening during use of concrete structuresDemolishing and recyclingTransportations in each stage
World Cement Production in 2011
Total: 3.6 billion tonnes
China57.3%
Japan1.4%
India6.2%
Asia(excl.China,India,Japan)
12.9%
Africa4.7%
USA1.9%
America(excl.USA)5.2%
CIS2.5%
CEMBUREAU7.3%
Europe(excl.CEMBUREAU) *
0.3%Oceania0.3%
*Including EU27 countries not members of CEMBUREAU
World Steel Production in 2011
China45.9%
Japan7.2%
U.S.5.8%
India4.9%
Russia4.6%
Korea4.6%
Germany3%
Ukraine2.4%
Brazil2.4%
Other19.2%
Total: 1.490 billion tonns
CO2 Emissions in Concrete and Construction Industries
Concrete Industry5 billion tons (17% of 29 billion tons, CO2
emissions of fossil fuel origin in 2007)Construction industry
6.3 billion tons (21.7% of 29 billion tons)
“These figures may be conservative!”
CO2 Emissions in Concrete and Construction Industries in the Future
Concrete Industry10 billion tons (34% of 29 billion tons, CO2
emissions of fossil fuel origin in 2007)Construction industry
12.6 billion tons (43% of 29 billion tons)
“Again, these figures may be conservative!”
Efficiency and innovation in cement manufacture (To be cont’d)
CO2 emissions in cement production‐ Decarbonation of limestone‐ Combustion of fossil fuels
Possible measures to reduce CO2 emissions‐ Reduction of limestone used‐ Reduction of fuel by lowering incinerationtemperature while improving thermalefficiency of incineration.
Efficiency and innovation in cement manufacture (Cont’d)
Use of biomass (regarded as carbon‐neutral)‐ Its availability is limited.
Use of fossil‐related waste‐ CO2 is less than that from virginfuels.
International Comparison of Energy Consumption in Cement‐Clinker Production
140
180
120
100
8060
160
4020
Japa
n
USA
Can
ada
W. E
urop
e
Aus
tral
ia &
NZ
Chi
na
SE. A
sia
Rep
. of K
orea
Indi
a
Afr
ica
Mid
dle
Eas
t
E. E
urop
e
S. a
nd L
. Am
eric
a
Form
er U
SSR
Unit‐based CO2 Emission in Cement Manufactures
Japa
n
USA
Can
ada
W. E
urop
e
Aus
tral
ia &
NZ
Chi
na
SE. A
sia
Rep
. of K
orea
Indi
a
Afr
ica
Mid
dle
Eas
t
E. E
urop
e
S. a
nd L
. Am
eric
a
Form
er U
SSRU
nit-
base
d C
O2 em
issi
ons
(kg-
CO
2/kg-
cem
ent)
0
0.2
0.4
0.8
1
1.2
0.6
Possibility of CO2 Reduction by Improving Energy Efficiency
Under some assumptions, the energy consumption can be reduced to 67% of the current level by introducing Japanese technology.Then, CO2 emissions can be reduced by 13.2%.
Prospects towards Sustainable Concrete Construction (To be cont’d)
Efficiency and innovation in cement manufactureSCMHigh‐range water‐reducing agentHigh performance concrete and its application to structural designEfficient transport and executionEfficient use, demolition, and recycling
Prospects towards Sustainable Concrete Construction (Cont’d)
Development of innovative technologiesZero‐carbon or minus carbon concretenet‐zero energy building
Establishment of impact evaluation and environmental design systemsRating systems, ISO standardsbuilding information modeling
How to balance of safety, durability, and resilience with environmental stewardship?
ESSENCE OF SUSTAINABILITY
A New Technology in UK (NOVACEM)
Carbon negative footprint cement (absorb up to 100kg more CO2 than the production process emissions).Cement base: magnesium oxide and hydrated magnesium carbonatesProduction process: Accelerated carbonation of magnesium silicatesApplication: masonry products
Belite‐Calcium Sulfoaluminate‐felite(BCSAF) Type Clinker (Lafarge)
Ingredients: limestone, bauxite and sulfate calciumCO2 emission reduction from raw materials: 25% (in actual kiln)Calcination temperature: 1,300℃ or less (15% reduction in fuel consumption)
Fluidized Bed Cement Kiln System
Suspension pre-heater
Rotary kiln Air quenching cooler
Rotary Kiln System
CO2 reduction:10~25%NOx reduction: 40%
SuspensionPre-heater
Fluidized bed sintering kiln
Packed bed cooler
Fluidized Bed Kiln System
Fluidized bed granulating kiln
Fluidized bed quenching cooler
Carbonation
CO2 absorption method
Reduction of cementquantity
-195
absorb CO2
Environmentconscious concrete
Ordinaryconcrete
439
-200
-100
0
100
200
300
400
500
CO
2em
issi
on(kg
-CO
2/m3 ) 182
Main materials:1) FA as cement substitute2) Special admixture (γ‐2CaO‧SiO2) that reacts
with CO2
Normal flow of exhaust
Inlet CO2 :15~20%
Outlet CO2 : 11~13%
Carbon Negative Concrete Block
Future Perspectives on Sustainability
Global population reached 7 billions.Balance among safety/reliance, resource/energy consumption, goods/ service supply, and environmental burden is a key in sustainability.Three scenarios are possible as the function of population, living standard, and resource/energy efficiency.
Scenarios on Resource/Energy ‐Service/Goods ‐ Environmental Impact Scenario 1
Popu.: increase, Living stan.: rise Resource/Ener. Efficiency : current level
Scenario 2Popu.: increase, Living stan.: riseResource/Ener. Efficiency : rise in proportionto them
Scenario 3Popu.: increase, Living stan.: riseResource/Ener. Efficiency : increase more than the increase of popu. and living stan.
Scenarios on Resource/Energy –Service/Goods – Environmental Burden
Pres
ent
Pres
ent
Present
Prod
uctio
n of
goo
ds a
ndse
rvic
es
Env
iron
men
talb
urde
n
Resources and energy consumption
123
Environmentalburden
How about Concrete and Construction Industries!
Robust buildings and infrastructure are the basis of sustainability. If the population increases and living standards rise, demand for buildings and infrastructure development increases.As a direct or indirect consequence, resource and energy consumption grows.Therefore, scenario 3 should be the target of our industry, too.
What are the Problems to be Solved?
The balance among resources/energy consumption (environmental aspects), economy, and safety/reliability (social aspect) is important for the sustainability of our society.
There are still issues regarding the robustness of existing buildings and infrastructure.
The available technology and assessment rules for reducing all negative impacts are not adequate.
Conflict between Structural Safety and Environmental Issues
If a large degree of redundancy is adopted, the degree of safety increases. But, this generally increases the amount of resources and energy used. If a low level of redundancy is adopted, highly efficient resource and energy consumption results, but the degree of safety decreases in respect of actions exceeding the assumed level.
Design Basis of Concrete Structure
It is not economically practicable to design a structure that completely excludes destruction by unforeseen great external forces that may occur in the future. Therefore, it is necessary to provide a level of performance that holds damage to the level of partial destruction without collapse of the entire structure, in the case of an unforeseen great action of very low probability.
Facts on Damage of Structures in Japan Disaster
Wooden houses were destroyed by the tsunami. Many bridges just fell down by the tsunami.
Reinforced concrete buildings escaped destruction from the tsunami and therefore many people’s lives were saved.
The columns and beams of Tohoku‐Shinkansenviaducts suffered damage, but it amounted only to localized destruction, not whole collapse. As a result, train accidents were prevented and the viaduct recovered within a short time.
Rehabilitation by jacking‐up
Scenarios on Safety and Environmental Burden
Scenario 1: Increasing the degree of safety under current technology leads to an increase in environmental burden.
Scenario 2: Improvement to materials and structure allow the degree of safety to be increased without increasing environmental burden.
Scenario 3: Introduction of innovative technology in materials and structure reduces environmental burden and increase safety.
Scenarios on Safety and Environmental Burden
1
2
3
Pres
ent
Present
Env
iron
men
talb
urde
n
Safety
An Example of Scenario 3
RC rigid frame viaduct‐ Ordinary viaduct with underground beams‐ Innovative viaduct without undergroundbeam, but with spiral reinforcement in columns and point pre‐load in pile
RC Rigid Frame Viaduct‐ Side View ‐
Steel tube
PC plate
Cast-in-place pile
Steel tube
RC Rigid Frame Viaduct‐ Elevation View ‐
PC plate
G.L.
Steep tube
Cast-in-place pile
Point pre-load
Cast-in-place pile Footing
beam
With underground beams Without underground beam
CO2 Emissions from Construction of RC Rigid Frame Viaduct
Slabs
Beams
Columns
Han
drai
ls /
whe
el g
uard
sSc
affo
lds
/ fa
lsew
orks
Pile
Footingbeams
Materials production Tr
ansp
orta
tions
Executions
Slabs
Beams
Columns
Han
drai
ls /
whe
el g
uard
sSc
affo
lds
/ fal
sew
orks
Pile
Materials production
Tran
spor
tatio
ns
Executions
CO2em
ission
s (t)
0
200
500
100
300
400
With underground beams Without underground beams
Preload
Injection bag ofcement milk
Enhancement of bearing capacity of
pile
Conventional Technology (with underground beam)
New technologies(without underground beams)
Damaged No damage
Viaducts of railways
Analysis of Results
The introduction of new technologies into viaduct structure: ‐ decreased environmental burden (CO2 andresources)‐ increased safety (no damage in earthquake)
This is “scenario 3”, ideal direction!
Concluding Remarks (1)
Human being invented a great idea “sustainability” at the end of 20th century.From the idea, our problems have become quite clear.For ourselves and future generations, it is very important to create the reasonable systems that achieve sustainable society.Concrete is the keystone for that.
Concluding Remarks (2)
In contemporary society, almost all people utilize infrastructure and spend long periods of time inside houses and buildings, which are built with concrete.Therefore, creating safety structures with low environmental burden, which is the essence of sustainability, is the responsibility of those of us working in the concrete and construction industry.
“Concrete, there’s no other alternative”