Takafumi NOGUCHI The University of Tokyo

Lifecycle Perspective of Technologies and Properties of Recycled Aggregate Concrete in Japan NRMCA Concrete Sustainability Takafumi NOGUCHI The University of Tokyo noguchi@bme.arch.t.utokyo.ac.jp 2010 International Concrete Sustainability, Dubai, 1

Content NRMCA Concrete Sustainability Introduction History of Measures on Recycling Political Measures Standardization History of Recycling Technology Recycling technologies for existing structures Completely Recyclable Concrete Conclusions 2010 International Concrete Sustainability, Dubai, 2

Environmental Problems in Concrete Industries Global warming Resource depletion Waste disposal 2010 International Concrete Sustainability, Dubai, 3

Building Related CO 2 Emission Japan s total CO 2 emission 1.2 billion tons Other industries 64% Housing construction Commercial building 5% constructionbuilding 6% repair 1% Energy for housing Energy for operation commercial 11% building operation 13% 36% 2010 International Concrete Sustainability, Dubai, 4

CO 2 Emission from Concrete Industries 2 Portland cement: 1 ton CO 2 : 075 0.75 ton Decarbonation of limestone (60 %) Fossil fuel combustion (30 %) Concrete: 1 m 3 CO 2 : 0.35-0.45 ton Cement production (0.25 ton) Others (0.1 0.2 ton) 2010 International Concrete Sustainability, Dubai, 5

Resource Input into Construction Industries Total Construction CONCRETE Total: 2,000 (million is the t/year) second most Total: 1,000 widely (million consumed t/year) substances on Earth, after water! LIQUID STONE:NEW ARCHITECTURE Others IN CONCRETE (National Building Museum in Washington D.C.) Construction 1,000 (million t/year) 50% Wood Steel Concrete 500 (million t/year) 50% 2010 International Concrete Sustainability, Dubai, 6

Waste Output from Construction Industries Industrial Waste Total: 406 (million t/year) Construction Waste Total: 79 (million t/year) Chemical Steel Others Energy Agriculture Wood Sludge Others Asphalt concrete Pulp Construction 79 (million t/year) 17% Concrete 35 (million t/year) 42% 2010 International Concrete Sustainability, Dubai, 7

in rea e waste posal ar ion m 3 ) Possible nal disp (milli P fi NRMCA Concrete Sustainability Final Disposal Sites for Waste 220 200 180 160 140 120 Scarcity of residual capacity of final disposal areas Industrial Waste: 412 (million t/year) General Industrial 1993 1994 1995 1996 1997 1998 1999 2010 International Concrete Sustainability, Dubai, 8 2000 2001 2002 2003 Resource-recycling recycling society

Content NRMCA Concrete Sustainability Introduction History of Measures on Recycling Political Measures Standardization History of Recycling Technology Recycling technologies for existing structures Completely Recyclable Concrete Conclusions 2010 International Concrete Sustainability, Dubai, 9

Recycling Ratio of Concrete 1990 1995 2000 2005 Recycle Disposal Ministry of Construction Action Plan for Construction By-products 94 Promotion Plan for Construction Waste Recycling 97 Basic Law for Establishing a Recycling-based Society Construction Material Recycling Act Law on Promoting Green Purchasing 0 10 20 30 40 Emission of Concrete Lumps (million t) For road subbase For mechanical stabilization underground 2010 International Concrete Sustainability, Dubai, 10

t) Productio on (million NRMCA Concrete Sustainability Predicted Amount of Future Concrete Waste 600 500 400 300 200 100 Demand for road subbase Concrete production Concret e waste Greatest part of future aggregate for concrete 0 1950 2000 2050 Imbalance between Year supply of concrete waste demand for road subbase Recycling From Quantity-oriented to Quality-oriented 2010 International Concrete Sustainability, Dubai, 11

Content NRMCA Concrete Sustainability Introduction History of Measures on Recycling Political Measures Standardization History of Recycling Technology Recycling technologies for existing structures Completely Recyclable Concrete Conclusions 2010 International Concrete Sustainability, Dubai, 12

Standardization of Recycled Aggregate 1977 Building Contractors Society Draft standard for the use of recycled aggregate g and recycled concrete 1994 Ministry of Construction Quality requirements Provisional quality standard for reuse of concrete by-products Density: higher Water absorption: Accreditation criteria of recycled aggregate for lower building concrete 1999 Building Center of Japan 2000 Ministry i of International Trade and Industry TR A0006 (Low quality recycled aggregate concrete) 2005-20072007 Japan Industrial Standards Committee JIS A 5021, 5022 and 5023 (Recycled aggregate for concrete, Recycled Concrete) 2010 International Concrete Sustainability, Dubai, 13

Specified Values of Recycled Aggregate in JIS Coarse aggregate Fine aggregate JIS A5021 (Class H) Density (g/cm 3 ) 2.5 or more Absorption (%) 3.0 or less Density (g/cm 3 ) 2.5 or more JIS A5022 23or 2.3 22or 2.2 5.0 or less (Class M) more more JIS A5023 (Class L) - 70orless 7.0 - Absorption (%) 3.5 or less 7.0 or less 13.0 or less 2010 International Concrete Sustainability, Dubai, 14

Applications of Recycled Aggregate Class - H Class - M Class - L Scope of application No limitations it ti are put on the type and segment for concrete and structures with a nominal strength of 45MPa or less JIS A 5308 (Ready-mixed concrete) allowing to use Class-H RA for normal strength concrete Members not subjected to drying or freezing-and-thawing action, such as piles, underground beam, and concrete filled in steel tubes Backfill concrete, blinding concrete, and leveling concrete 2010 International Concrete Sustainability, Dubai, 15

Content NRMCA Concrete Sustainability Introduction History of Measures on Recycling Political Measures Standardization History of Recycling Technology Recycling technologies for existing structures Completely Recyclable Concrete Conclusions 2010 International Concrete Sustainability, Dubai, 16

Classification of Recycling Technologies Demolished Concrete Lumps NRMCA Concrete Sustainability Jaw Crusher Impact Crusher Vibratory Sieves Heating Tower Vibratory Sieves Cone Crusher Coarse Aggregate Scrubber Road Subbase, Backfill Low Quality Recycled Coarse Aggregates Vibratory Sieves Low Quality Recycled Fine Aggregates Fine Aggregate Scrubber High Quality Recycled Coarse Aggregates Vibratory Sieves High Quality Recycled Fine Aggregates Powder (a) Road Subbase (b) Low Quality Recycled Aggregates (c) High Quality Recycled Aggregates 2010 International Concrete Sustainability, Dubai, 17

Problems in Conventional Technology to Produce High-quality Recycled Aggregate Repeated crushing Recovery percentage decreasing Fines generation increasing Water Absorption (%) Recovery Percentage (%) 5-10mm Recycled Fine Aggregate not less than 10mm Size of Supplied Concrete Lumps Recycled Coarse Aggregate Powder Gravel Sand Cement Paste No 1st 2nd 3rd Number of Crushing Treatment No 1st 2nd 3rd Original Concrete Crushing Treatment 2010 International Concrete Sustainability, Dubai, 18

Mechanical Scrubbing Equipment for High-quality Recycled Aggregate NRMCA Concrete Sustainability Concrete lumps Eccentric tubular mill External cylinder Scrubbing Motor Recovery Transmission gear 2010 International Concrete Sustainability, Dubai, 19

Application of Mechanical Scrubbing Method Old apartment Houses 12 x 4-storied Concrete lump: 11,500 t New apartment Houses 7 x 9-19-storied Recycled coarse aggregate: 3,000 t Recycled concrete volume: 3,000 m 3 ( Total concrete volume:40,000 m 3 ) 2010 International Concrete Sustainability, Dubai, 20

Heated Scrubbing Equipment for High-quality Recycled Aggregate NRMCA Concrete Sustainability Dust Chamber 2 nd Scrubbing Machine 1 st Scrubbing Machine Hot Elevator Rotary Kiln Sieve Filler Tank Recycled Coarse Aggregate 5- By-product Recycled Fine Aggregate - 20mm Powder 5mm 2010 International Concrete Sustainability, Dubai, 21

Mechanism of Heated Scrubbing Heating at Rubbing 300 C process Concrete rubble Weakening of hardened cement paste Removal of powdered cement hydrate 2010 International Concrete Sustainability, Dubai, 22

Application of Heated Scrubbing Method Storehouse : Upper structure : SRC 6-storey Basement structure : RC 1-storey Building area : 12,800m 2 Total floor area : 62,100m 2 Total volume of recycled concrete: 25,000m 3 2010 International Concrete Sustainability, Dubai, 23

Content NRMCA Concrete Sustainability Introduction History of Measures on Recycling Political Measures Standardization History of Recycling Technology Recycling technologies for existing structures Completely Recyclable Concrete Conclusions 2010 International Concrete Sustainability, Dubai, 24

Problems in Current Recycling Forwardprocess productio n Existing technology Nosotropic technology No recycling-conscious design applied Materials diffused into a wide range of industries Finally disposed Quality degradation, Unstable supply, Unstable price, Unstable distribution, Increasing environmental impact 2010 International Concrete Sustainability, Dubai, 25

Concept of Completely Recyclable Concrete New technology Proactive Technology Upstream (inverse) processes incorporated Components of concrete completely recycled into concrete Resource conserved Resource circulated in a closed system 2010 International Concrete Sustainability, Dubai, 26

Cement-recovery Type Completely Recyclable Concrete Demolition Operation Crushing & Milling Calcination Semi-closed-loop Clinker Gypsum Construction Recycled cement Production of CRC Aggregate Concrete whose binders, additives and aggregates are all made of cement or materials of cement, and all of these materials can be used as raw materials of cement after hardening 2010 International Concrete Sustainability, Dubai, 27

Changes in CO 2 Emissions and Dumped Concrete 200 200 5% of concrete replaced with cement-recovery type CRC every year 150 CO2 Emission Dumped concrete 150 CO2 Emission Dumped concrete 100 100 Dumped Concrete 50 CO 2 Emission 0 0 50 100 150 200 250 Elapsed year (1) As it is 50 Calcined limestone never emits CO 0 2. 0 50 100 150 200 250 Elapsed year (2) Production of CRC 2010 International Concrete Sustainability, Dubai, 28

Application of Cement Recovery Type CRC for Eco-Pole Supply of Pole Remove and Transportation Manufacture of Pole Placing of concrete Use and Operation Closed Recycle of Concrete Pole Crushing and Classifying Steel Recycling Limestone Supply Cement Supply Steam cured Raw Material for Cement Limestone Mining Circulation of Cement Manufacture of Cement Removal of form 2010 International Concrete Sustainability, Dubai, 29

Aggregate-recovery Type CRC Demolition Crushing & Sievingi Chemical treatment Operation Calcination Recycled Closed-loop Construction Recycled cement aggregat Clinkere Physical treatment Production of CRC Surface modified aggregate 2010 International Concrete Sustainability, Dubai, 30

Recovery and Mechanical Property of Aggregate-recovery recovery Type CRC NRMCA Concrete Sustainability ry ratio (% ) Recove No treatment Chemical Physical 90 80 70 60 50 40 Crushed stone W/C=60% Gravel Streng th (MPa) No treatment Chemical Physical 60 50 40 30 20 10 Trade-off relationship remained Crushed stone W/C=40% Aggregate recoverability increased Mechanical properties of concrete decreased d Gravel 2010 International Concrete Sustainability, Dubai, 31

Advanced Aggregate Recovery-type CRC Concrete strength enhancement Aggregate surface modification Increase bonding force between coarse aggregate and mortar Fine SCM: pozzolanic reaction Mineral powder: mechanical fiti friction 330 C 610 C C at 10sec 30sec Surface modification treatment Aggregate Mortar Aggregate recoverability Inclusion of dielectric material Selective heating by microwave Weakening aggregate surface Recovery of aggregate with low energy < Microwave heating > < After microwave heating > 2010 International Concrete Sustainability, Dubai, 32

Mechanical Properties in Advanced Aggregate Recovery-type CRC NRMCA Concrete Sustainability Increase 2010 International Concrete Sustainability, Dubai, 33

Aggregate Recovery Ratio in Advanced Aggregate Recovery-type CRC Recov very rati io (%) Original coarse aggregate Fine aggregate Paste 120 100 80 60 40 20 0 Decreas e Increase O1 O2 O3 SP80 2010 International Concrete Sustainability, Dubai, 34

CO 2 Emission in Concrete Recycling Process CO2 emis ssion (kg/ /t-concre ete) 40 35 30 25 20 15 10 5 0 Decreas e Heated- scrubbing Mechanical- scrubbing Others Scrubbing Microwave heating 30sec 60sec 90sec 2010 International Concrete Sustainability, Dubai, 35

Sustainable Resource Recycling Concrete Society Concrete structure Long-lived Demolition and recovery Complete separation Recycled coarse aggregate Coarse aggregate Fine aggregate By- product powder Modification Modified coarse aggregate Fine aggregate Cement Microwav e heating Little CO 2 emission Cement factory High-purity Ca Recycled fine aggregate (under technology development) Demolition and recovery Use as cement raw material Completely recyclable structure 2010 International Concrete Sustainability, Dubai, 36

Content NRMCA Concrete Sustainability Introduction History of Measures on Recycling Political Measures Standardization History of Recycling Technology Recycling technologies for existing structures Completely Recyclable Concrete Conclusions 2010 International Concrete Sustainability, Dubai, 37

Conclusion NRMCA Concrete Sustainability Toward sustainable resource-recycling recycling society Concrete recycling in closed system Current method: Some technical and social problems Adoption of technology enhancing resource conservability at the stage of design Completely recyclable concrete New technology with aggregate surface modification and microwave radiation Overcoming inherent conflicting properties in concrete recycling Achieving high performance of concrete Energy saving and small CO 2 emission in concrete recycling Fully recovering original aggregate Generating cement raw materials which never emit CO 2 2010 International Concrete Sustainability, Dubai, 38

Thank! you for your kind attention! على حسن استماعكم م! أشكرآم noguchi@bme.arch.t.u- tokyo.ac.jp 2010 International Concrete Sustainability, Dubai, 39