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

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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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