state-of-the-art recycling technologies for building materials in japan part 1 cement & concrete...

State-of-the-art Recycling State-of-the-art Recycling Technologies for Building Technologies for Building

Materials in JapanMaterials in Japan

Part 1 Cement & ConcretePart 1 Cement & Concrete

Takafumi NOGUCHI

CONTENTSCONTENTS

1. Resource Recycling Model of Concrete

2. Environmental Aspect of Cement Production

3. Environmental Aspect of Aggregate Production

4. Environmental Aspect of Concrete Production

5. Concrete Recycling

1. RESOURCE RECYCLING 1. RESOURCE RECYCLING MODEL OF CONCRETEMODEL OF CONCRETE

RESOURCE RECYCLING MODEL RESOURCE RECYCLING MODEL OF CONCRETE (1)OF CONCRETE (1)

Total material input 2,000,000,000 t/year– Buildings and civil structures 1,000,000,000 t/year

• Concrete production 500,000,000 t/year• Steel production 32,530,000 t/year• Wood 17,000 t/year

Total waste 458,360,000 t/year– General waste 52,360,000 t/year– Industrial waste 406,000,000 t/year– Concrete lumps 35,000,000 t/year


Final disposal sites for industrial waste

120

140

160

180

200

220

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

Pos

sib

le w

aste

infi

nal

dis

pos

al a

rea

(mill

ion

ton

)

GeneralIndustrial


Typical Life Phases of Concrete Product / Concrete Structure

Raw material acquisition

mining of aggregatesmining of stones for cement productionenergy sources and energy productionwater supply

Realizationproduction of concrete and concrete elementsdesign construction

Life enddemolitionreuserecyclingdisposallandfill

Utilization use maintenancerepairrenovation

Life phases of concrete product


Potential Chance to Influence Degree of Environmental impact

Life Cycle Phases of Concrete Structure

Design Construction UtilizationDemol/Recycl

Conceptual DesignTechnology Concept Detailed Design

Construction Demolition RecyclingUse

MaintenanceRepair

The Chance to Influence Degree of Environmental Impact / Environmental Efficiency

Potential to influence Ei

Waste disposal, landfill


Life Cycle of Concrete Structure– Material and energy flows and consequent environmental impacts


Material Flows of Concrete

LimestoneLimestone 84,267 CementCement 82,181

(Import: 1,228, Export: 7,564 ）

Others 28,617Gravel, SandGravel, Sand301,000

Crushed StoneCrushed Stone412,000

Others 16,000

Asphalt 3,379

Recycled CrushedRecycled CrushedStoneStone51,180

Slag 12,331Fly Ash 4,551Others 8,702

COCO22

44,725

Aggregate for ConcreteAggregate for Concrete405,404

Road Subbase Materials and OthersRoad Subbase Materials and Others320,955

Aggregate for Asphalt Concrete53,821

ConcreteConcrete475,842(including Cement-based Products)

Asphalt Concrete71,400

BuildingsCivil Structures

New Stocks

Recycle on Site

ExistingStocks

Waste DisposalWaste Disposal1,780

Concrete LumpsConcrete Lumps 35,040Asphalt Concrete 16,140

Asphalt Concrete Lumps14,200

Unit ：1,000t

Enormous Amounts of Concrete Stocks

Discharge of Concrete < 10% of Input

ENVIRONMENTAL ASPECT ENVIRONMENTAL ASPECT OF CEMENT PRODUCTIONOF CEMENT PRODUCTION

ENVIRONMENTAL ASPECT OF ENVIRONMENTAL ASPECT OF CEMENT PRODUCTION (1)CEMENT PRODUCTION (1)

Raw Materials and Energy for 1 ton of Normal Portland Cement

Raw Materials (kg) Energy

Limestone 1,093Fuel (kg)[Coal Equivalent (6,200 kcal/kg)]

105Clay 203

Silica Stone 76

Iron Ore 30Electric Power (kwh)[including co-generation]

99Gypsum 34

Total 1,436

Highest level of energy efficiencythanks to the energy conservation measurestaken during the period between 1970 and 1990


Fuel for Cement– Coal : 85%

• from China, Australia, Russia, and Indonesia

– Petroleum coke : 10%– Industrial waste : 3%– Heavy oil : 1%


Recycling Ecosystem of Cement Production

PrintingIncineration ash,Waste plastics

Electric &Electronic appliances

Sludge,Waste plastics,

Used tonerCartridges,

CFCs

TextileSludge,

Waste plastics

Electricpower

Coal ash,EP dust(ash),

Gypsum

AgricultureWaste plastics

FisherySeashells,Wastes

Nonferrousmetals

Molding sand,Sludge, Slag,

Gypsum

LocalMunicipality

Sewage sludge,Sludge generated byWater purification,Municipal waste,Incineration ash

Buildingmaterial

Waste board,Sludge

Paper&PulpSludge,

Incinerationash

ConstructionWaste plastics

Food productWaste diatomaceous

Earth,Waste plastics,

Distillery residue,Sludge Petroleum

Waste clay, Sludge,Waste oils,

Used catalysts,DOC, FOC

ChemicalsSludge,

Waste plastics,Gypsum

SteelSlag, EP ash

CementAutomobile

Molding sand,Paints residue,

Used tires

PachinkoUsed

Pachinkomachines


Waste and Byproducts Utilized by Cement Industry

Type Uses Amount (t)Blast Furnace Slag Raw Material, Additive 12,162,000Fly Ash Raw Material, Additive 5,145,000Byproduct Gypsum Additive 2,643,000Sludge Raw Material 1,906,000Nonferrous Slag Raw Material 1,500,000Steelmaking Slag Raw Material 795,000Ash Dust Raw Material, Fuel 734,000Coal Waste Raw Material, Fuel 675,000Casting Sand Raw Material 477,000


Waste and Byproducts Utilized by Cement Industry

Type Uses Amount (t)Scrap Tire Fuel 323,000Reclaimed Oil Fuel 239,000Oil Waste Fuel 120,000White Clay Waste Raw Material, Fuel 106,000Plastic Waste Fuel 102,000Others - 433,000Total - 27,359,000

RecentlySewage sludge, Incineration ash from municipal solid waste


Use of sewage sludge and incineration ash from municipal solid waste– the high temperature safely decomposes

hazardous materials including dioxins– no new waste is generated– requires no additional incineration

facilities– extends the service lives of final disposal

sites


Utilization of Blast Furnace Slag and Fly Ash

CementLandfill

Civil StructuresBuildings Others

Foundation IimprovementOthers

Cement

Export

Road

ConcreteAggregate

Civil Structures

Blast Furnace Slag (24,518,000t) Fly Ash (6,919,000t)


Changes in cement production by type

0

2000

4000

6000

8000

10000

12000

1975 1980 1985 1990 1995 2000

年度

t生産量（万）

フライアッシュセメント高炉セメントポルトランドセメント

Fiscal Year

Fly Ash CementSlag CementPortland Cement

Production (x10,000 t)99,270,000 tons

in 1996

ratio of blended cement production has been gradually increasing


The increasing trend of blended cement production because of– Expected increase in the number of thermal

power plants producing coal ash– Expected increase of crude steel production

affected by the construction rush in economically buoyant China

– Law on Promoting Green Purchasing in 2001 in which blast-furnace slag cement and fly ash cement were designated as green procurement products


“Ecocement” recently developed in Japan– made using incineration ash from municipal soli

d waste and sewage sludge– Dioxins completely decomposed at a high temp

erature without being resynthesized• rapidly cooled to below 200C in a cooling tower• captured in a bag filter and an active coke-packed towe

r

– Heavy metals contained in incinerated ash• recovered/concentrated• delivered to nonferrous metal factories for recycling


Chemical compositions of portland cement and incineration ash

Limestone 47 - 55Clay 45 - 78 10 - 26 3 - 9

Silica sand 77 - 96Iron source 40 - 90

Gypsum 26 - 41 37 - 59

12 - 31 23 - 46 13 - 29 4 - 7 1 - 4

CaO SiO2 Al2O3 Fe2O3 SO3

62 - 65 20 - 25 3 - 5 3 - 4 2 - 3CementIncin. Ash

(%)


Raw materials combination– Ecocement replaces limestone and clay with incineration ash

Silica sand4%

Normal Portland Cement

Limestone78%

Clay16%

Others2%

Ecocement

Limestone52%

Sewage sludge9%

Others1%

IncinerationAsh 38%


Chemical Composition of Ecocement

0.010.632.064.22.85.221.21.5NPC

0.900.509.257.32.510.015.30.8Rapid

Hardening Type EC

0.040.263.761.04.48.017.01.1Normal

Type EC

ClR2OSO3CaOFe2O3Al2O3SiO2Ig.

Loss

(%)


Physical Properties and Quality of Ecocement

Densityg/cm3

Spec. Surf.cm2/g

Initial Seth-min

FinalSeth-min

Comp. Str., N/mm2

3h 1d 3d 7d 28d

N-EC 3.17 4250 2-35 4-25 - 10 30 41 53

RH-EC 3.13 5300 0-30 0-50 10 25 38 53 58

NPC 3.16 3350 2-22 3-10 - 15 29 44 61W/C=0.50, S/C=3.0


“Ecocement” recently developed in Japan

Ecocement

Bug Filter

Mill

Gypsum

Clinker

Clinker Cooler

Rotary KilnTank for

HomogenizationTank

Bug Filter DenitrationAir

Smelter

DrainageHeavy Metal RecoveryCrusher

Incinerated AshRaw Sludge

Limestone, etc.

Raw MaterialsGasWater

Administrative office & bottom ash storage facilities

Rotary dryer

Raw mat. mill

Homogenizing tank

Flue gas cooling tower

Bag filterRotary kiln

Heavy metal refining process

Fly ash tank

Lot area; 16,700m2

366m

34m

80m

58m

Gas treatment

Ecocement tank

Panoramic view of Ichihara Ecocement plantPanoramic view of Ichihara Ecocement plant


Ichihara Ecocement Corporation (Rotary kiln)


Application for construction Application for construction Application for construction

Application for civil works Application for civil works Application for civil works

External wall Concrete block Concrete roof

Inter rocking block Concrete block Marine product

Applications of Ecocement to various concrete products

ENVIRONMENTAL ASPECT ENVIRONMENTAL ASPECT OF AGGREGATE OF AGGREGATE

PRODUCTIONPRODUCTION

ENVIRONMENTAL ASPECT OF ENVIRONMENTAL ASPECT OF AGGREGATE PRODUCTION (1)AGGREGATE PRODUCTION (1)

Changes in aggregate productionCrushed StoneRiver GravelPit GravelHill GravelSea GravelOthers

Production (million t)

19631965196719691971197319751977197919811983198519861987198819891990199119921993199419951996199719981999200020012002

949 million tons in 1990

Crushed stone and Crushed/pit sand

have become major

Good quality river sand and river gravel have become depleted

Causingexposure of bedrock on the bottom of the sea erosion of embankmentsendangering sand spits and fishing grounds


Changes in aggregate production– Absolute ban on collection of sea gravel and sea

sand being implemented – Regulations on crushed stone collection being

tightened from the aspect of natural landscape protection

– Ready-mixed concrete plants in Tokyo receiving not only crushed limestone from western Japan but also river sand from China

• Wide-area transfer of aggregate over regions and borders


Aggregate, 70% by volume of concrete, anticipated as a recipient of waste and byproducts from other industries

Type Standard

Blast Furnace Slag Aggregate JIS A 5011-1

Ferronickel Slag Aggregate JIS A 5011-2

Copper Slag Aggregate JIS A 5011-3

Electric Arc Furnace Oxidizing Slag Aggregate JIS A 5011-4

Molten Slag Aggregate JIS A 5031

Fly Ash Calcined Lightweight Aggregate

ENVIRONMENTAL ASPECT OF ENVIRONMENTAL ASPECT OF CONCRETE PRODUCTION (1)CONCRETE PRODUCTION (1)

Changes in concrete production

Concrete Production

Concrete Waste

Concrete Wastefrom Buildings

Concrete Wastefrom

Civil Structures

Production and Waste (million t)

600

500

400

300

200

100

0

1950 2000 2050 Year


decrease due to reductions in investment in new construction of buildings and civil structures

ENVIRONMENTAL ASPECT OF ENVIRONMENTAL ASPECT OF CONCRETE PRODUCTION (2)CONCRETE PRODUCTION (2)

Waste and byproducts generated from RMC plants– Returned concrete from 1m3 of RMC : 0.009

m3

– Sludge cake resulting from 1m3 of RMC : 5.88 kg

Returned ConcreteMixerAgitator Truck


WashingWater Waste



Supernatant WaterSludge WaterSupernatant WaterSludge Water

Recovered WaterRecovered Water

Sludge SolidSludge Solid Sludge CakeSludge Cake

Mixing WaterCoarse Aggregate

Fine AggregateRoad Subbase

Final Disposal

CONCRETE RECYCLINGCONCRETE RECYCLING

CONCRETE RECYCLING (1)CONCRETE RECYCLING (1)

Recycle ratio of demolished concrete

0 1000 2000 3000 4000

1990年度

1995年度

2000年度

tコンクリート塊排出量（万）

再利用処分ReuseDisposal

1990

1995

2000

Emission of Concrete Lumps (million t)

0 10 20 30 40

Effort by the Ministry of ConstructionRecycling Plan 21 Construction Recycling Promotion Plan ’97

For road bottoming materialsFor mechanical stabilization materials


Discrepancy between– the amount of concrete lumps generated

and

– the amount of concrete lumps removed from construction sites

– Reason• In-situ recycling as road bottoming and backfill

materials• Inclusion in dirt and soil to be disposed of at

landfill sites


Recycle in Apartment Complex

Recycle Plant

SieveCrusher

Demolished Building

Sound-proof Wall

60-20mm

Powder

40-0mm

Backfilling Gravity Retaining Wall Concrete Pavement

Packing

BasementFoundationImprovement

Packing

Road Subbase


Changes in concrete production

Concrete Production

Concrete Waste

Concrete Wastefrom Buildings

Concrete Wastefrom

Civil Structures

Production and Waste (million t)

600

500

400

300

200

100

0

1950 2000 2050 Year


decrease due to reductions in investment in new construction of buildings and civil structures

Premature deteriorationEnds of their service livesDemolished


Reuse of concrete lumps as aggregate for concrete– Enormous amount of concrete lumps

generated– Demand for concrete lumps for roads

decreasing• New road construction gradually decreasing• Method of repairing existing roads shifting

from repavement to “mill and overlay”


Recycling process of demolished concrete lumps

Demolished Concrete Lumps

Jaw Crusher

Impact Crusher

Vibratory Sieves

Road Subbase, Backfill

Cone Crusher

Vibratory Sieves

Vibratory Sieves

Low Quality Recycled Coarse

Aggregate

Heating Tower

Coarse Aggregate Scrubber

Fine Aggregate Scrubber

Low Quality Recycled Fine

Aggregate

High Quality Recycled Coarse

Aggregate

High Quality Recycled Fine

Aggregate

Powder

Vibratory Sieves

(a) Road Subbase (b) Low Quality Recycled Aggregate (c) High Quality Recycled Aggregate


Uses for concrete lumps determined by– the qualities of the recycled material

• Density• Water absorption

– depending on» percentage of cement paste contained within» adhering to the surfaces of original aggregate

– depending on production method


Today’s conventional concrete recycling– Roadbed material– Aggregate for concrete excluding structural

use


High quality recycled aggregate– Repeating crushing

• Recovery percentage decreasing• Fines generation increasing

– Carrying out high level treatment such as heating and grinding in order to minimize the adhering cement paste


Quality and recovery percentage of recycled aggregate

5-10mmnot less than10mm

No 1st 2nd 3rd

Number of Crushing Treatment

Water Absorption (%)

Recovery Percentage (%)

Recycled Fine Aggregate

Recycled CoarseAggregate

Powder

Size of SuppliedConcrete Lumps

Sand

Gravel

Cement Paste

No 1st 2nd 3rd Original ConcreteCrushing Treatment


Efficient equipment for producing high quality recycled aggregate (1)– Heated scrubbing

Recovery ofFine Aggregate

Recovery ofCoarse Aggregate

Sieve

Tube MillTube Mill

Fine PowderFineAggregate

CoarseAggregate

Bug FilterHeating DeviceFilled withConcrete Lumps


• Heated scrubbing

Heating at

300CRubbing process

Concrete rubbleWeakening of

hardened cement paste

Removal of powdered

cement hydrate

Input Hopper

Heating Tower

Fine Aggregate Mill

Classifier

Dart Collector

Powder Storage Tank

Recycled Coarse Aggregate

Recycled Fine Aggregate

Coarse Aggregate Mill

Heated scrubbingHeated scrubbing


Recycled structural aggregates& by-product powder


Quality of Recycled AggregatesA

bs

orp

tio

n

(%)

Oven-dry density (g/cm3)

0

2

4

6

8

10

12

14

2.0 2.2 2.4 2.6

Virginaggregate

Recycled Coarse/ Former systems

Recycled Fine/Former systems

Coarse & fine/CLC system


An Example of Application

Acoustic Laboratory ・ Construction period:11/2000-9/2001 ・ Place:Koto-ku, Tokyo ・ Structure:Reinforced concrete structure, three levels above the ground ・ Building area:363.41m2

・ Total floor area:667.75m2

Structure B : ・ Place:Kitakyushu city・ Year of completion: 1988

Structure A : ・ Place:Chofu city, Tokyo・ Year of completion: 1960


Concrete plant

Recycled aggregate plant



Efficient equipment for producing high quality recycled aggregate (2)– Mechanical scrubbing-1 (eccentric tubular

type) Concrete Lumps

EccentricTubular Mill

Motor

ExternalCylinder

Scrubbing

Transmission GearRecovery

Mechanical scrubbing-1 Mechanical scrubbing-1 (eccentric tubular type)(eccentric tubular type)


Eccentricrotor device

2nd sieve1st sieve

Product

After the rotor device

CrushedConcrete lump


Old apartment Houses12 x 4-storiedConcrete lump: 11,500 t

New apartment Houses7 x 9-19-storiedRecycled coarse aggregate: 3,000 tRecycled concrete volume: 3,000 m3

( Total concrete volume:40,000 m3 )


Efficient equipment for producing high quality recycled aggregate (3)– Mechanical scrubbing-2 (screw type)

Cylinder HollowInput

Middle Cone Ejection Cone

OutletRotary Blade


Efficient equipment for producing high quality recycled aggregate (3)– Mechanical scrubbing-2 (screw type)


Efficient equipment for producing high quality recycled aggregate (4)– Wet scrubbing and gravity classification

Drum

RodsSupply Exit

Concrete Lumps

Water Level Range in Air

Chamber

Recycled Aggregate with Low Density

Recycled Aggregate with High Density

Water LevelLow Density Zone

High Density Zone


Efficient equipment for producing high quality recycled aggregate (4)– Wet scrubbing and gravity classification

Political Aspects Political Aspects

Prime Minister, Junichiro Koizumi

The Manifesto of the Democratic Party of Japan (opposition party)– “From Concrete to People, People, People”

Why concrete is not recycled into concrete?

Government official

“It is because there is no industrial standard.”

suffered a crushing defeat in the general election



JIS A 5021, March 2005– Recycled aggregate for concrete - class H

(RA-H)• High qualityHigh quality recycled aggregate and used as

aggregate for JIS A 5308 (Ready-mixed concrete)• The amount of deleterious substancesdeleterious substances tested through

comparisoncomparison with several confirmatory samples including each deleterious substance


JIS A 5021, March 2005– Recycled aggregate for concrete - class H

(RA-H)• The minimum rate of testingminimum rate of testing and the criteria of alkali-criteria of alkali-

silica reactivitysilica reactivity dependent on the identification of the identification of the attribute of original aggregatesattribute of original aggregates

• Unless identified, tested at frequent intervals and treated as an aggregate of potential alkali-silica reactivity

• Must be produced in a plant assessed, surveyed and assessed, surveyed and certifiedcertified by an approved body


• Physical Properties Requirements for RA-H

Coarse aggregate Fine aggregate

Oven-dry density (g/cm3) not less than 2.5 not less than 2.5

Water Absorption (%) not more than 3.0 not more than 3.5

Abrasion*1 (%) not more than 35 NA

Material passing 75 m sieve (%) not more than 1.0 not more than 7.0

Percentage of solid volume for evaluation of particle shape (%)

not less than 55 not less than 53

Chloride ion content (%) not more than 0.04

*1 : for pavement


• Limits of Amount of Deleterious Substances for RA-H

Category Deleterious substances Limits (mass%)

A Tile, Brick, Ceramics, Asphalt concrete 2.0

B Glass 0.5

C Plaster 0.1

DInorganic substances other than

plaster 0.5

E Plastics 0.5

F Wood, Paper, Asphalt 0.1

Total 3.0

CONCRETE RECYCLING (32)CONCRETE RECYCLING (32) Large amount of by-product fines

– Resulting from production of high quality recycled aggregate

– Possible uses • Addition to road bottoming• Cement material• Concrete addition• Asphalt filler• Ground improving material• Inorganic board material

– Demands• Quality stabilization• Reduction of quality control cost


Ground improvement

Raw material of cement


Recyclable concrete like steel and aluminum

Production process of concrete – Conventional downstream approach

• focusing on– Cost reduction– Efficiency in production

– New production systemNew production system• incorporating upstream (inverse) processes in

consideration of recyclability

CONCRETE RECYCLING (35)CONCRETE RECYCLING (35) Conventional Material Flow of Concrete Recycling

heating

rubblingcrush

impactcrush

frictioncrush

Loop3

demolition

use and managenment

Production of Structural ConcreteLoop 1 (Target : Structural Concrete）Loop 2 (Target : Non-structural Concrete）Loop 3 (Target : Sub-base Materials)

environmentaldisruption

structuralaggregate

Subbase Materials

sieving

non-structuralaggregate

subbasematerials

Inspection

environmentaldisruption

demolition

demolition

compressivecrush Loop1

Non-structural Concrete

sieving

sieving

compressivecrush

impactcrush

compressivecrush

Loop2

Structural Concrete

waste em

issions

(concrete rubble,asphalt concrete rubble,mixed rubble）


Completely recyclable concrete (CRC)– Cement recovery type CRC

Concrete whose materials are entirely usable after hardening as materials of cement or recycled aggregate, since all the binders, additions, and aggregate are made of cement or materials for cement.



Precast ConcreteFoundationsMade from CRCin Kita-kyusyu



Perfect Recycle Housein Kita-kyusyu


Completely recyclable concrete (CRC)– Aggregate recovery type CRC

Concrete in which the aggregate surfaces are modified without excessively reducing the mechanical properties of the concrete, in order to reduce the bond between aggregate and the matrix, thereby permitting easy recovery of original aggregate.


Completely recyclable concrete (CRC)– Aggregate recovery type CRC

Chemical treatment

Physical treatment

The principal ingredient of the coating agent is mineral oil. The agent hydrolyzes in alkali conditions of fresh concrete, forming acidic matter and indissoluble amalgam on the surface of the aggregate. The surface coating results in decreased amounts of cement hydrate, and leads to decreased adhesive strength between aggregate and paste matrix, allowing easy recovery of the original aggregate.

The coating agent is a water-soluble synthetic resin emulsion, which is applied in process of abrasion, and which is chemically stable in fresh concrete. The uneven surfaces of virgin aggregate become smoother, the shape of the aggregate being roughly maintained. This has the effect of decreasing adhesive strength between aggregate and paste matrix.


Material flow should be further optimized in cooperation with other industriesin cooperation with other industries as part of the resource recycling of society as a whole, reflecting back on the abundant resource consumption of abundant resource consumption of concreteconcrete and the long service liveslong service lives of buildings and civil structures.


Research and development involving Research and development involving “recycling” as a keyword should clarify “recycling” as a keyword should clarify what what recycling design ought to berecycling design ought to be and and how it how it ought to be carried outought to be carried out and examine if it is and examine if it is essentially effective in establishing a essentially effective in establishing a sustainable global environment for the sustainable global environment for the present and future. Otherwise, present and future. Otherwise, environmental technology intended to environmental technology intended to improve the issue of the global environment improve the issue of the global environment could be chained to another vicious circle.could be chained to another vicious circle.


Toward the future, in addition to Toward the future, in addition to technologies for treating existing stock, technologies for treating existing stock, it is vital to established production it is vital to established production systems whereby systems whereby new stock serves as new stock serves as resources by actively introducing resources by actively introducing lifecycle design involving recycling lifecycle design involving recycling designdesign, which incorporates, which incorporates

inverse processes of productioninverse processes of production..

AssignmentAssignment

Select one building material in one country except concrete in Japan.

Investigate the annual amount of production, recycle and final disposal of the selected material in the country.

Investigate the recycling technologies of the selected material and the uses of the recycled material.

You can download the today’s presentation file atYou can download the today’s presentation file at

http://bme.arch.t.u-tokyo.ac.jp/class_info/index.htmlhttp://bme.arch.t.u-tokyo.ac.jp/class_info/index.html

state-of-the-art recycling technologies for building materials in japan part 1 cement & concrete...

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