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Transcript of Construction and Demolition Waste (C&DW)...
DongUk CHOI
Department of Architectural Engineering
Hankyong National University, Korea
Chairman, Green Committee for Concrete, KCI
Construction and Demolition Waste (C&DW) Management
Sustainable Development
Sustainable Development
3 Pillars of Sustainable Development
Population Increase and Resource Depletion
Sustainable Development
1987 UN Brundtland Commission
(Our Common Future, Report by UN Brundtland Commission, 1987)
"Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”
Dr. Brundtland, Norwegian Priminister(1981, 1986-1996)
3 Pillars of Sustainability
3 Pillars of Sustainability
Sustainable development requires reconciliation of environmental, societal
and economical demands.
환경보존
3 Pillars of Sustainability (2005 World Summit on Social Development)
Population Increase and resource Depletion
Earth is 4.56 billion year old.
Human existed for the last 200,000 years only (0.004% of earth age).
Human population in 1800 was only 1 billion.
In 2012, the population is 7 billion: rapid increase after industrial revolution.
Natural resources and energy consumption and green house gas emission
are all increasing at an alarming rate,
Change in Human Population (Essential Earth, 2008)
Environmentally Important Events
The Limits to Growth, 1971
UN Environmental Program, UNEP, 1972
Our Common Future, Report by UN Brundtland Commission,
1987
Montreal Protocol, 1989
Earth Summit, Rio de Janeiro, and Agenda 21, 1992)
UN Framework Convention on Climate Change (UNFCCC),
1993)
Kyoto Protocol, 1997
Kyoto Protocol, 1997
Kyoto Protocol was adopted in the 3rd Conference of Parties (COP3)
in Kyoto, 1997.
38 advanced countries agreed to reduce emission of the following six
green house gases GHG) to prevent further global warming:
CO2, CH3, N2O, PFCs, HFCs, SF6
It was resolved to achieve reduction of GHGs by 5.2% on average
based on that emission in 1990 during 2008-2012.
1. INTRODUCTION
2. REUSE/RECYCLING OF C&D WASTES
3. RECYCLING OF BY-PRODUCTS
4. LIFE-CYCLE-BASED APPROACHES
5. CONCLUDING REMARKS
Conte
nts
1. INTRODUCTION
Status of Construction in Korea
Policies on Sustainability
Waste Management
Status of Waste Generation
Laws and Regulations on Waste Management
Status of Construction in Korea – 1/2
Construction industry has been very important in Korea.
Total revenue of construction industry was U$ 100 billion (Domestic)
and U$ 56 billion (Abroad) in 2011.
Construction industry takes 6% of GNP.
Construction-related employment is 8% (direct) and it is 14% (including
indirect employment).
Environmental impacts from construction and operation of buildings and
civil engineering structures are very large:
Consumption of resources = 30% Energy consumption = 35% GHG emission = 35% Waste generation = 50%
25,261 17,323 21,216 25,858 39,034
47,231 43,787 53,278 49,604
37,702 44,984 41,857 41,833 42,123 45,153
20,365 22,247
25,347 23,764
29,519
34,769 34,950
45,845 38,084
27,536 29,012 29,251 30,349 27,741 26,298
0
20,000
40,000
60,000
80,000
100,000
120,000
Civil Engineering Project
Building Project
case
1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
418 208 276 343 380
493 641 567 627 718
834 717
587 562 654
307
228 189
204 236
263
290 293
276 258
329 375
492 376
353
0
200
400
600
800
1,000
1,200
1,400
Civil Engineering Project
Building Project
Mil
ion
Dol
lar
1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
Global financial crisisIMF● Constructionorders(cases)
● Constructionorders(US Dollar)
Status of Construction in Korea – 2/2
1 U$ = 1,100 Korean Won
Resource Use by Structural Types
aggregates and stone
steel
ceramic
cement
wood
others
Use
of
reso
urc
es/
are
(kg/m
2)
avera
ge
wood
SRC
RC
steel
Structural type 12
GHG Emission related to Construction
Total GHG emission related to construction, operation of buildings,
transportation of building products, and production of building products
is 33% of national emission.
production of building products13%
transpor-tation3%
construction1%
operation of commercial facilities8%
operation of residential buildings 8%
others67%
C&D61.7(51.4%)
Commercial36.8(30.7%)
Household17.9(14.9%)
All waste120(100%)
Overall Status of Waste Generation
Total amount of waste generation was 120 million tons in 2006.
Total amount increased from 83 million tons (2000) to 120 million tons
(2006): increased by 45% in 6 years.
Generation of household and commercial wastes has been steady.
C&D waste generation (51.4% of all wastes) has been increasing.
Waste generation – overall (2006)
unit: million ton
special designation, 3.6 (3.0%)
Concrete, asphalt concrete,brick, block(78.7%)
combustible(1.6%)
mixed(14.2%)
Misc. soil, sand, gravel(5.2%)
C&D waste total61.7(100%)unit: million ton
C&D waste generation (2006)
Status of C&D Waste Generation – 1/2
C&D wastes rapidly increased from 28.8 million tons (2000) to 61.7 million
tons (2006): increased by 114% in 6 years.
Portion of C&D wastes among all wastes also increased from 34.7% (2000)
to 51.4% (2006).
Concrete, asphalt concrete, blocks, etc. took 78.7 %
non-combustible(0.3%)
C&D waste generation increases because many structures built in
1960s~80s during economic boom approach end of service life.
C&D waste generation will further increase in the future.
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
1 2 3 4 5 6 7 8 9
Demolished
concrete
Demolished
asphalt
concrete
Other C&D
wastes
Total amount
C&D wastes
2006
2007
2008
2009
2012
2013
2014
2015
2016
Concrete40.3(65.3%)
Asphalt concrete7.9(12.8%)
Other C&D wastes13.5
(21.9%)
C&D waste generation (2006) C&D waste generation (2006~16)
unit: million ton
Status of C&D Waste Generation – 2/2
C&D waste total61.7
(100%)Projected values
Laws and Regulations on Waste Management
1986, Waste Management Law- to establish national plan on waste management in every 10 years- regulation of permit and facilities for waste treatment companies- responsibility of reporting by business enterprises that generate wastes
1992, Law on Resource Saving and Acceleration of Reuse/Recycling - to minimize waste generation and maximize reuse/recycling toward
realization of closed-loop resource recycling system
2005, Law on Acceleration of C&D Waste Reuse/Recycling- step-by-step demolition of C&D wastes- utilization of recycled aggregates from demolished concretes- safe treatment of hazardous wastes
2007~2011, 1st national C&D Waste Management Plan (WMP)2012~2016, 2nd national C&D WMP
Waste Management Law (1986)
1st law on waste management that established the basic framework.
Government, cities and municipalities
Ministry of Environment establishes and updates national waste management plan every 10 years.
Governors of provinces, mayors of cities, and heads of municipalities report status of waste generation, waste treatment, waste reuse/recycling, and waste treatment companies and operate waste treatment facilities.
Waste treatment companies
need permit and maintain minimum facilities.
Business enterprises
report type and amount of wastes. specially-designated wastes: report type, amount of wastes and
treatment plan.
Law on Resource Saving and Acceleration of Reuse/Recycling (1992)
Enacted to minimize waste generation and maximize reuse/recycling and move toward closed-loop recycling society. This law includes clauses directly related to C&D wastes.
Owner of land or building separates generated wastes for
reuse/recycling.
Constructor minimizes the waste generation from construction and
minimizes the hazardous effect from the generated wastes.
In an urban development project, developer selects structure’s type and
materials that are suitable for reuse/recycling, use recycled aggregates,
and ensure proper treatment of wastes generated from such
development.
Law on Acceleration of C&D Waste Reuse/Recycling (2005) – 1/2
Enacted to accelerate reuse/recycling of C&D wastes. C&D wastes are defined as construction wastes that weigh 5 tons or more.
Ministry of Environment establishes and updates C&D waste
treatment plan in every 5 years.
Governor of provinces, mayors of cities, and heads of municipalities report the C&D waste generation by type, C&D waste treatment, reuse/recycling, and status of C&D waste treatment companies every year.
Ministry of Environment constructs C&D waste information management system (ALLBARO).
Client
Client includes cost for C&D waste separation, storage, treatment, reuse/recycling in the construction document.
Law on Acceleration of C&D Waste Reuse/Recycling (2005) – 2/2
C&D Waste Treatment Company are classified as follows:
waste collection and transportation company, waste middle treatment (receive, separate and treat wastes) company, waste comprehensive treatment (collect, transport, treat wastes)
company.
Constructor
Constructor establish step-by-step demolition plan. Constructor may establish waste treatment facility in the field. Constructor reports expected amount of wastes by type and
treatment plan at the beginning of construction.
1st National C&D Waste Management Plan (2007-2011)
Objectives of the 1st 5-year plan included the following:
C&D waste reduction by step-by-step demolition; C&D wastes generated in the field and those received by waste
treatment companies are registered in the national waste information management system (ALLBARO, www.allbaro.or.kr);
Effective utilization of recycled aggregates; and Safe treatment of hazardous waste (e.g. asbestos).
Improvements after the 1st national plan includes the following:
All C&D waste information by constructor and waste treatment companies are recorded on-line and
Rate of use of demolished concrete (e.g. application of recycled aggregates) drastically improved.
2nd National C&D Waste Management Plan (2012-2016)
Objectives of the 2nd national plan included the following:
Improvement on the national waste information management: additional data input by the user of treated wastes;
Construction of life-cycle inventory data of C&D wastes; and Reduction on the amount of mixed wastes.
ALLBARO
Waste generation byconstructor
Waste treatment by company
User of treated wastes(constructor)
data in/outdata in/out
no data
National waste information management system and waste flow
REUSE/RECYCLING OF C&D WASTES
Demolished Concrete
Scrap Steel
Status of C&D Waste Generation (2009)
conc, asphalt conc, bricks, blocks54.6 (81.7%)
non-combustible other than conc.2.8 (4.1%)
Combustible0.8 (1.1%)
mixed 8.7 (13.1%)
In 2009, total C&D waste generation (67 million tons) was 51.2% of all
wastes (131 million tons).
C&D wastes are largely divided into 4 groups: (1) concrete, asphalt
concrete, bricks, blocks, etc., (2) non-combustible wastes other than
concrete and bricks, (3) combustible wastes, (4) mixed wastes.
unit: million ton
Status of C&D waste generation (2009)
C&D waste total 67 million tons
Demolished Concrete
In 2009, 42.1 million tons of demolished concrete was generated
(63% of all C&D wastes).
Effective recycling rate was 36%.
(definition of effective recycling: usage on road sub-base construction
or equivalent, concrete blocks, and recycled aggregate for concrete).
Concrete products such as concrete blocks = 6% Production of concrete as recycled aggregates = 1.5%
Recycledaggregates
Quality of Recycled Aggregates – 1/2
KS F 2573 (Recycled aggregates for concrete) was announced in 1999.
Concretes with 27 MPa strength class and under can be manufactured using recycled C.A. (30% replacement by vol.).
Concretes with 21 MPa strength class and under can be manufactured using recycled C.A. and F.A. (30% replacement by vol.).
Method of application of recycled aggregates for concrete (KS F 2573)
Compressive
strength
(MPa)
Aggregates Typical usage
C.A. F.A.
21~27 natural
coarse aggregates
and
recycled
coarse aggregates
natural
fine aggregates
only
column, girder, slab
, load-bearing wall,
etc.
< 21 natural fine aggregates
and
recycled fine aggregates
concrete block, roa
d base, filler materi
al for concrete, etc.
Quality of Recycled Aggregates – 2/2
Quality of recycled aggregates production has also been controlled by
Ordinance on Certification and Quality Control of Recycled
Aggregates.
Required properties KS F 2526
Aggregates
for concrete
KS F 2573
Recycled aggregates
for concrete
C.A. F.A. C.A. F.A.
Physical
properties
Density (g/cm3) ≥ 2.5 ≥ 2.5 ≥ 2.5 ≥ 2.2
Water absorption (%) ≤ 3.0 ≤ 3.0 ≤ 3.0 ≤ 5.0
Stability (%) ≤ 12 ≤ 10 ≤ 12 ≤ 10
Abrasion (%) ≤ 40 -- ≤ 40 --
Particle shape (%) -- -- ≥ 55 ≥ 53
Hazardous
material
(%)
Silt ≤ 0.25 ≤ 1.0 ≤ 0.2 ≤ 1.0
% passing
0.08 mm sieve
Abrasive use ≤ 1.0 ≤ 3.0 ≤ 1.0 ≤ 7.0
others ≤ 1.0 ≤ 5.0 ≤ 1.0 ≤ 7.0
Foreign
matters
Organic materials (% by vol.) -- -- -- ≤1.0
Inorganic materials (% by wt.) -- -- -- ≤1.0
Quality requirements of normal vs. recycled aggregates
Recycled Aggregate Production – 1/5
Typical production procedures: (1) concrete crushing, (2) separation of
foreign matters from concrete, (3) classifying.
Concrete crushing is performed in three steps:
Jaw crusher for initial crushing: concrete pieces of 80~200 mm diameter
Cone crusher for refined crushing: 0~80 mm diameter Roll crusher or impact crusher (5 mm or smaller)
Jaw crusher
Recycled Aggregate Production – 2/5
Cone crusher Roll crusher
Recycled Aggregate Production – 3/5
Separation process of various foreign matters
Visual selection, Picking up metallic objects using magnets, or Using gravity and air blower or using buoyancy in water.
Visual selection
p/up using magnets
Using buoyancy in
water
Air blowing
Recycled Aggregate Production – 4/5
Classifying is a process to separate aggregates of different diameters or
fine aggregates from coarse aggregates using various methods.
Slopedvibrating screen
Spiral
Trommel
Cyclone
Currently available national standards on recycled aggregates utilizing
C&D wastes and industrial by-products in Korea include the following:
KS F 2543 Recycled Copper Slag aggregates for Concrete KS F 2544 Recycled Blast Furnace Slag Aggregates KS F 2572 Recycled Aggregates for Asphalt Concrete KS F 2573 Recycled Aggregates for Concrete KS F 2574 Recycled Aggregates for Road Pavement KS F 2583 Recycled Zinc Slag Aggregates for Concrete KS F 4571 Recycled Electric Arc Furnace Oxidation Slag Aggregate for
Concrete
Recycled Aggregate Production – 5/5
Need for new standard on “recycled aggregates for concrete products” :
Quality required to make concrete products (e.g. concrete bricks and
blocks) need not be as strict as to produce structural concrete.
To promote the use of recycled aggregates, Korean Building Law includes
a relaxation clause from regulation on building area and height for
concrete structures :
+5% for use of 15% or more recycled aggregates +15% for use of 25% or more recycled aggregate.
Methods to Increase Use of Recycled Aggregates
conc. aggregates
conc. products
road sub-base construction
Quality requirements of recycled aggregates
Target effective recycling rate is 45% by 2016.
Scrap Steel – 1/4
Construction industry is a consumer of about 40% of steel produced
in Korea.
In 2007, Korea produced 54 million tons of steel where the amount
produced by blast furnace and electric furnace was 58% and 42%,
respectively.
In the same year (2007), 28.4 million tons of scrap steel was generated.
Korea has no iron ores and scrap steel is important resources for steel
industry.
Scrap steel is energy-efficient as it consumes only 74% of energy for
steel production when using scrap steel rather than raw materials.
35
All household, commercial, C&D scrap steel is separately collected,
transported and reused.
80% of scrap steel is used in electric arc furnace to produce steel reinforcement and structural steel shapes, etc.
16% is used by steel-making furnace (converter furnace). 4% is used for other purposes.
Scrap steel consumption is expected to increase in the future.
In 2015, the expected scrap steel amount is 33 million tons, 16% increase from 28.4 million tons in 2007.
25% scrap steel is imported from U.S., Japan, Russia, etc.
Scrap Steel – 2/4
Scrap Steel – 3/4
Result of material flow analysis (MFA) of steel (2003) reveals the
following:
53.3 million tons was domestically produced; 14.5 and 15.6 million tons were exported and imported, respectively; Total amount circulated was 54.8 million tons; 43% was used for construction; Use of scrap steel was 50.1% of iron ores; and 27% of scrap steel was imported.
MFA is also under progress for important non-ferrous metals such as
aluminum, copper, zinc, lead, tin, etc. to construct a statistical system
and establish supply/demand strategies.
Scrap Steel – 4/4
scrap
Steel
(0.42)23,067
Iron ore
(0.84)46,058
transportation
machinery etc.
elec./electronic
construction
others
steel slag
reuseDomestic produc-tion
scrap steel export
Techno Sphere
landfill
domestic
import
domestic
import
System Boundary
accumsteel
Material flow analysis (MFA) of steel (2003)
Building Construction Specification - 1/2
Architectural Institute of Korea (AIK) Standard Building Construction
Specification recommends the following sequence of step-by-step
demolition for a building structure:
Household waste Specially designated waste Mechanical and electrical equipment Exterior and interior finishing materials Roof finishing and water-proofing materials Structure
Demolished C&D wastes need to be brought out of field
immediately or temporarily stored in a designated area for the
C&D wastes.
Building Construction Specification – 2/2
Final draft of 2013 AIK Standard Building Construction
Specification requires constructor to submit Environmental
Management Plan during Construction in the following five
areas:
Reduction of GHG emission Reduction on use of natural resources Increase the reuse/recycling amount of C&D wastes and
industrial by-products Environmental management on construction site Utilization of water resources
Environmental impact categories can be required by client brief
or relevant laws and regulations.
RECYCLING OF SPECIALLY-DESIGNATED BY-PRODUCTS
Steel Slag
Coal Ash
Recycling for Cement Manufacturing
CO2 Reduction in Mix Sesign
Steel Slag
Steel slag (blast furnace slag, converter slag, and electric furnace slag)
is specially designated by-products in Korea along with coal ash,
concrete, asphalt concrete, bricks, and construction waste wood.
Waste treatment of specially designated by-products is required by
Law on Resource Saving and Acceleration of Reuse/Recycling.
Steel makers in Korea produced 68.5 million tons of steel (42.1 million
tons from blast furnace and 26.4 million tons from electric arc furnace) in
2011.
Steel slag generation is 40% of steel production.
Steel slag generation is increasing by 30% with addition of new blast
furnaces (Hyundai Steel) starting from 2011.
Blast Furnace Slag
Steel by-product by POSCO was 18.6 million tons in 2009.
Amount of steel slag was 43% of steel production: blast furnace slag
(63%, 8.9 million tons) and steel-making slag (37%, 5.2 million tons).
99% of blast furnace slag was utilized for blended cement and as
aggregates, fertilizer, etc.
Utilization of blast furnace slag (2009)
Blast furnace slag total = 8.9 million tons
44
Blast furnace slag aggregates
Electric Furnace Slag
About 20% of steel slag is electric arc furnace slag.
Korean Standard Association (KSA) has recently developed a new
standard on the use of electric arc furnace oxidation slag as concrete
coarse and fine aggregates.
There are still technical concerns on the potential volume expansion due
to free CaO and free MgO in case of aggregates that have not been
through sufficient ageing.
Blast furnace and converter Electric furnace
From coal-burning power plant, 8.35 million ton of coal ash was
generated in 2009.
6.8 million ton was fly ash (82%) and 1.5 million ton was bottom ash
(18%).
About 68% of fly ash and 40% of bottom ash are being recycled.
Target recycling rate by 2012 is 75%.
Coal Ash
Utilization of coal ash (1994~2007)
Fly Ash
66% of fly ash was recycled in 2009 while the usage was as mineral
admixture for concrete and raw material for cement, etc.
It is mandatory in Korea to use at least 10% fly ash replacement of
cement when building a coal-fired power plant.
Utilization of fly ash (2009)
Bottom Ash
Only 27% of bottom ash was reutilized in 2009.
To increase utilization, there is a new pilot production facility ready for production of light-weight aggregates utilizing bottom ash.
Production capacity of this pilot plant is 200,000 m3 per year and the plant will begin mass production in 2013.
Typical physical properties of light-weight coarse aggregates produced using bottom ash
Density
(g/cm3)
Absorp-
tion (%)
F.M. DRUW
(kg/m3)
Shape
1.48 19.3 6.3 906 round
By-Products in Cement Manufacturing – 1/2
Manufacturing 1 ton of Type-1 Portland cement in Korea means the
followings:
Consumption of 1.6 ton of raw materials.
Use of 3.24 GJ of energy.
Release of 768 kg-CO2.
Utilization of 263 kg of recycled raw materials and by-products.
Alternative fuels include used tires and used plastics.
Recycled raw materials include coal ash, steel slag, sludge, used
molding sand, etc.
Utilization of by-products and wastes may increase by about 10% in the
future.
Heavy Metals in Cement
Utilization of industrial by-product and wastes in cement raised public
concern as to the environmental effects on land and local communities.
2005 investigation revealed that in some cases some heavy metal
content, for example hexavalent chromium, exceeded the legal limit.
A series of investigations resulted in strengthened legal limit,
establishment of new test method, strengthened governmental
regulations on the environmental control of the cement kiln: for example,
haxavalent chromium limit was lowered from 30 mg to 20 mg/kg-
cement.
Currently, 6 heavy metals are monitored: Cr, Cu, Cd, Pb, As, Hg.
Contents of heavy metals in cement are reported on-line through
websites of Ministry of Environment and Korea Cement Industrial
Association.
CO2 Reduction in Mix Design – 1/3
Concrete production actively utilizes SCM.
Evaluation of CO2 reduction by using SCM is needed.
0
5
10
15
20
25
30
35
0 20 40 60 80 100 120 140 160
f ck (MPa)
Ci (
kg
/m 3
· M
Pa
-1)
OPC
OPC+FA
OPC+GGBS
OPC+FA+GGBS
OPC+SF
OPC+FA+SF
0
5
10
15
20
25
0 20 40 60 80 100 120 140
f ck (MPa)
Ci (
kg
/m 3·
MP
a -1
)
OPC
OPC+FA
OPC+GGBS
OPC+FA+GGBS
OPC+SF
OPC+FA+SF
: y =109.4x-0.62
, R2=0.84
: y =94.4x-0.61
, R2=0.65
: y =108x-0.68
, R2=0.59
: y =96.7x-0.74
, R2=0.34
: y =63.9x-0.5
, R2=0.60
: y =45.3x-0.44
, R2=0.45
ckfCOCi emission)/ ( 2
CO2 index:
Ci decreases with increasing concrete strength. The tendency is more pronounced for concrete with fck < 60 MPa
Effect of unit concrete design strength on Ci
0
5
10
15
20
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Replacement ratio of SCM
Ci (
kg
/m 3·
MP
a -1
)OPC+FA (fck=20~30MPa)
OPC+FA (fck=60~70 Mpa)
OPC+GGBS(fck=23~30 Mpa)
OPC+GGBS(fck=60~70 Mpa)
OPC+SF(fck=24~30 Mpa)
OPC+SF(fck=60~70 Mpa)
OPC+FA(f ck=23~30 MPa)
OPC+FA(f ck=60~70 MPa)
OPC+GGBS(f ck=23~30 MPa)
OPC+FA(f ck=60~70 MPa)
OPC+SF(f ck=25~30 MPa)
OPC+SF(f ck=60~70 MPa)
Best-fit curve
OPC+FA
OPC+GGBS
OPC+SF
CO2 Reduction in Mix Design – 2/3
Effect of SCM replacement ratio on Ci
Ci decreases with increasing SCM replacement ratio. OPC + FA mix tends to exhibit larger Ci than OPC + GGBS mix due to larger
amount of FA needed for the unit compressive strength
CO2 Reduction in Mix Design – 3/3
0
20
40
60
80
100
120
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Replacement ratio of FA, R F
CO
2 r
eduction p
erc
enta
ge r
ela
tive to '
OP
C c
oncre
te (
%)
R G =0.4
R G =0.3
R G =0.2
R G =0.1
R G =0.0
R G =0.7
R G =0.6
R G =0.5
Examples CO2-based SCM design chart (fck=30 MPa)
BRRRCO SGF
95.01.115.1
2 11.1
Based on regression analysis of mix design data, Ci can be formulated.
RF = replacement ratio of FA
RG = replacement ratio of GGBS
(1)
RS = replacement ratio of
silica fume
B = binder content
LIFE-CYCLE-BASED APPROACHES
LCA of Recycled Aggregate Production
LCA of Natural and Recycled Fine Aggregates
LCI Database
EPD of Building Products
LCA on Recycled Aggregate Production – 1/3
In Korea, many urban renewal projects are under progress.
Large quantity of C&D wastes is generated in the process of
demolishing existing structures.
Recycling cost and amount of CO2 emission were compared for two
different scenarios: (1) production of recycle aggregates using local
waste treatment companies near construction site and (2) on-site
production using on-site production facility.
The results revealed the followings:
Recycling cost is influenced by transportation distance and amount of waste concrete to recycle.
CO2 emission is influenced by transportation distance.
LCA on Recycled Aggregate Production – 2/3
LCA data used for analysis
Process Constructionequipment
Capacity (m3/hr)
Fuel consumption (1,000L)
CO2 emission (ton)
Installation of on-siterecycling facilities
truck crane (10t)trailer (20t)
-- 0.1 0.3
Load waste concrete onto trucks
back hoe (1m3) 17.7 90.0 254.2
Transportation of waste concrete
dump truck (15t) 14.74 203.3 574.1
Break waste concrete into pieces
backhoe (0.7m3) 10.0 22.0 62.1
Deliver concrete to recycling facility
tire loader (3.5m3) 44.85 76.1 214.9
Recycled aggregate production
traveling crusher(200t/hr)
63.53 180.6 510.0
Recycled aggregate post-processing
tire loader (3.5m3) 102.16 47.2 133.3
Load recycled aggregate onto trucks
tire loader (3.5m3) 122.6 39.3 111.0
Transportation of recycled aggregate
dump truck (15t) 14.74 278.9 787.6
Dismantle on-site recycling facilities
truck crane (10t)trailer (20t)
-- 0.1 0.3
Main factor that gives an environmental advantage for the on-site recycling is transportation distance.A sensitivity analysis results indicated that when the location of the nearby local treatment station is less than 10 km from construction site, then the on-site recycling becomes more expensive than the recycling using the local stations.
LCA on Recycled Aggregate Production – 3/3
Comparison of CO2 Emission in Two Different Recycling Processes
LCA of Natural and Recycled F.A. – 1/3
LCA (life-cycle analysis) of natural and recycled fine aggregates (F.A.)
was performed following ISO 14040/14044 (LCA):
System boundary: cradle to gate
5 different F.A.: fine aggregates from river, land, sea, crushed fine aggregates, and recycled fine aggregates.
F.A. - river
F.A. - sea
crushed F.A.
F.A - land
Fine aggregate supply (1994~2004)
LCA of Natural and Recycled F.A. – 2/3
System boundaries of aggregate production
Crushed aggregates Recycled aggregates
LCA of Natural and Recycled F.A. – 3/3
Environmental impact of recycled aggregate production is
significantly larger than that of natural aggregates.
Ex. Global warming potential (GWP):
Average of natural F.A. = 3.87 kgCO2-eq/m3
Recycled F.A. = 998 kgCO2-eq/m3
avera
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Use
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Environmental impact of aggregate production
Korea LCI database (KLCIDB, www.edp.or.kr) currently consists of about 400 industrial products.KLCIDB provides environmental performance evaluation following ISO 14040/14044 LCA (Life Cycle Assessment) procedures.Ex. Portland cement, reinforcing steel, ready-mixed concrete, etc.
LCI Database – KLCIDB
Type 1 Portland cement
APESS consists of a LCA program module and the LCI database.
The database currently consists of over 60 construction products.
Structural shapes, reinforcement, natural aggregates, recycled
aggregates, concrete block, clay brick, plywood, transportation of
ready-mixed concrete, ready-mixed concrete construction, structural
steel construction, etc.
LCI Database – APESS
LCA examples of aggregates and ready-mixed concreteProducts Energy
(GJ)Emissions
unit CO2 SOx NOx
Coarse aggregate 0.1591 kg/m3 11.146 0.0370 0.0281
Fine aggregate 0.0509 kg/m3 3.5761 0.0099 0.0147
Ready-mixed conc. (transportation) 0.0095 kg/km-m3 0.6603 4.3x10-8 0.0079
Ready-mixed conc. (construction ) 9.1928 kg/m2 187.01 0.1080 0.3120
EPD of Building Products
EPD is environmental product declaration following ISO 14020/14025
(Labels and declarations).
Drafting new standards on EPD of building products such as cement,
aggregates, and ready-mixed concrete is under progress.
Over 600 GR (good recycling) mark, environmental mark, carbon
footprint, and EPD of industrial and construction products have been
completed.
It is required by law to use environmentally-friendly products in
public construction.
There is also an incentive for using environmentally-friendly products
in bidding.
LCI database is also planned for C&D wastes.
CONCLUDING REMARKS
1. It is important to minimize C&D waste generation and
maximize reuse/recycling as the construction industry
is consumer of tremendous amount of natural
resources and energy as well as emitter of GHGs.
2. Establishment of effective strategies and enactment of
laws and regulations deem to be essential to achieve
this. In addition, provision of some incentives to users
of the recycled products deem to be necessary to
promote the use.
3. Innovational technological advances are much awaited.
4. Life-cycle approach is useful as it provides quantitative
tool to assess environmental impact of C&D waste
reuse/recycling.
5. Education on C&D waste management and
sustainability as early as possible to as broadly as
possible is of fundamental importance.
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