CONTENTS. of-the-art Recycling Technologies for Building Materials in Japan. Part 1 Cement & Concrete 1. STATE OF RESOURCE RECYCLING IN CONCRETE

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1 State-of of-the-art Recycling Technologies for Building Materials in Japan Part 1 Cement & Concrete Takafumi NOGUCHI CONTENTS 1. State of Resource Recycling in Concrete 2. Environmental Aspect of Cement Production 3. Environmental Aspect of Production 4. Environmental Aspect of Concrete Production 5. Concrete Recycling 1. STATE OF RESOURCE RECYCLING IN CONCRETE STATE OF RESOURCE RECYCLING IN CONCRETE (1) Total Resource input into concrete industries Total: 2,000 (million t/year) Construction Total: 1,000 (million t/year) Construction 1,000 (million t/year) 50% Wood Steel Concrete 500 (million t/year) 50% STATE OF RESOURCE RECYCLING IN CONCRETE (2) Industrial Waste Waste from concrete industries Total: 412 (million t/year) Chemical Steel Pulp Energy Agriculture Construction 75 (million t/year) 18% Construction Waste Total: 75 (million t/year) Wood Sludge Asphalt concrete Concrete 32 (million t/year) 41% STATE OF RESOURCE RECYCLING IN CONCRETE (3) Final disposal sites for industrial waste Possible waste in final disposal area (million ton) General Industrial

2 STATE OF RESOURCE RECYCLING IN CONCRETE (4) Concrete: 1 m 3 CO 2 emission from concrete crete industries CO 2 : ton Cement production (0.25 ton) ( ton) Portland cement: 1 ton CO 2 : 0.75 ton Decarbonation of limestone (60 %) Fossil fuel combustion (30 %) STATE OF RESOURCE RECYCLING IN CONCRETE (5) Typical Life Phases of Concrete Product / Concrete Structure Raw material acquisition mining of aggregates mining of stones for cement production energy sources and energy production water supply Realization production of concrete and concrete elements design construction Utilization use maintenance repair renovation Life phases of concrete product Life end demolition reuse recycling disposal landfill STATE OF RESOURCE RECYCLING IN CONCRETE (6) Potential Chance to Influence Degree of Environmental impact STATE OF RESOURCE RECYCLING IN CONCRETE (7) Life Cycle of Concrete Structure Material and energy flows and consequent environmental impacts Potential to influence E i Conceptual Design Detailed Design Technology Concept Construction Use Maintenance Repair The Chance to Influence Degree of Environmental Impact / Environmental Efficiency Demolition Recycling Waste disposal, landfill Design Construction Utilization Demol/ Recycl Life Cycle Phases of Concrete Structure STATE OF RESOURCE RECYCLING IN CONCRETE (8) Material Flows of Concrete CO 2 Limestone 44,725 84,267 Cement 28,617 Slag 12,331 Fly Ash 4,551 8,702 Cement 82,181 (Import: 1,228, Export: 7,564) Concrete Gravel, Sand 475, ,000 (including for Concrete Cement-based 405,404 Products) Buildings Civil Structures Discharge of Concrete < 10% New Stocks of Input Enormous Amounts of Concrete Stocks Crushed Stone 412,000 Existing Road Subbase Materials and Stocks 320,955 16,000 Recycled Crushed for Asphalt Concrete Stone 53,821 Asphalt Concrete 51,180 Asphalt 3,379 71,400 Asphalt Concrete Lumps 14,200 Concrete Lumps 35,040 Asphalt Concrete 16,140 Recycle on Site Waste Disposal 1,780 Unit:1,000t STATE OF RESOURCE RECYCLING IN CONCRETE (9) Environmental importance of concrete crete industries 10 billion ton of concrete produced annually worldwide 25 % of natural resources into concrete-related industries 7-10 % of global, manmade CO 2 from concreterelated industries Resource recycling system without extra CO 2 emission needed Natural resource conservation Prevention of global warming 2

3 ENVIRONMENTAL ASPECT OF CEMENT PRODUCTION CEMENT PRODUCTION (1) Raw Materials and Energy for 1 ton of Normal Portland Cement Raw Materials (kg) Energy Limestone 1,093 Fuel (kg) Clay 203 [Coal Equivalent (6,200 kcal/kg)] Silica Stone Iron Ore 30 Highest level of energy Electric Power efficiency (kwh) Gypsum 34 thanks to the energy [including conservation co-generation] measures Total 1, taken during the period between 1970 and 1990 CEMENT PRODUCTION (2) Fuel for Cement Coal : 85% from China, Australia, Russia, and Indonesia Petroleum coke : 10% Industrial waste : 3% Heavy oil : 1% CEMENT PRODUCTION (3) Recycling Ecosystem of Cement Production Local Construction Nonferrous Waste plastics Municipality Sewage sludge, metals Printing Sludge generated by Molding sand, Water purification, Sludge, Slag, Incineration ash, Paper&Pulp Municipal waste, Gypsum Waste plastics Steel Sludge, Incineration ash Slag, EP ash Incineration ash Chemicals Sludge, Building Fishery Waste plastics, Gypsum Seashells, Food product Wastes material Waste diatomaceous Cement Waste board, Earth, Sludge Automobile Waste plastics, Distillery residue, Molding sand, Sludge Petroleum Paints residue, Used tires Waste clay, Sludge, Electric Agriculture Waste oils, Waste plastics Used catalysts, Electric & power DOC, FOC Coal ash, Pachinko Electronic appliances EP dust(ash), Used Sludge, Gypsum Pachinko Waste plastics, Textile machines Used toner Sludge, Cartridges, Waste plastics CFCs CEMENT PRODUCTION (3) Waste and Byproducts Utilized by Cement Industry Type Uses Amount (t) Blast Furnace Slag Raw Material, Additive 12,162,000 Fly Ash Raw Material, Additive 5,145,000 Byproduct Gypsum Additive 2,643,000 Sludge Raw Material 1,906,000 Nonferrous Slag Raw Material 1,500,000 Steelmaking Slag Raw Material 795,000 Ash Dust Raw Material, Fuel 734,000 Coal Waste Raw Material, Fuel 675,000 Casting Sand Raw Material 477,000 CEMENT PRODUCTION (4) Waste and Byproducts Utilized by Cement Industry Type Uses Amount (t) Scrap Tire Fuel 323,000 Reclaimed Oil Fuel 239,000 Oil Waste Fuel 120,000 White Clay Waste Raw Material, Fuel 106,000 Plastic Waste Fuel 102, ,000 Total - 27,359,000 Recently Sewage sludge, Incineration ash from municipal solid waste 3

4 CEMENT PRODUCTION (5) 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 Concrete aggregate 10% CEMENT PRODUCTION (6) Utilization of Blast Furnace Slag and Fly Ash Civil structures 8% Road 17% Foundation improvement 1% Export 17% 2% Cement 45% Blast Furnace Slag (24,518,000t) Civil structures & Buildings 11% Landfill 21% 7% Fly Ash (6,919,000t) Cement 61% CEMENT PRODUCTION (7) Changes in cement production by type Production 生産量 (x10,000 ( 万 t) t) Fly フライアッシュセメント Ash Cement Slag 高炉セメント Cement Portland ポルトランドセメント Cement Fiscal 年度 Year 99,270,000 tons in 1996 ratio of blended cement production has been gradually increasing CEMENT PRODUCTION (8) 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 CEMENT PRODUCTION (9) Ecocement recently developed in Japan made using incineration ash from municipal solid waste and sewage sludge Dioxins completely decomposed at a high temperature without being resynthesized rapidly cooled to below 200 C in a cooling tower captured in a bag filter and an active coke-packed tower Heavy metals contained in incinerated ash recovered/concentrated delivered to nonferrous metal factories for recycling CEMENT PRODUCTION (10) Chemical compositions of portland cement and incineration ash (%) Cement Incin. Ash CaO SiO 2 Al 2 O 3 Fe 2 O 3 SO Limestone Clay Silica sand Iron source Gypsum

5 CEMENT PRODUCTION (11) Raw materials combination Ecocement replaces limestone and clay with incineration ash Sewage sludge Silica sand 4% 9% Clay 16% 2% Limestone 78% Normal Portland Cement Incineration Ash 38% 1% Limestone 52% Ecocement CEMENT PRODUCTION (12) Chemical Composition of Ecocement Normal Type EC Rapid Hardening Type EC NPC Ig. Loss SiO Al 2 O Fe 2 O CaO SO R 2 O (%) Cl CEMENT PRODUCTION (13) Physical Properties and Quality of Ecocement Density g/cm 3 Spec. Surf. cm 2 /g Initial Set h-min Final Set h-min 3h Comp. Str., N/mm 2 1d 3d 7d 28d CEMENT PRODUCTION (14) Ecocement recently developed in Japan Incinerated Ash Raw Sludge Limestone, etc. Crusher Tank Tank for Homogenization Bug Filter Denitration Air Smelter Drainage Heavy Metal Recovery Rotary Kiln N-EC RH-EC NPC W/C=0.50, S/C=3.0 Ecocement Bug Filter Clinker Cooler Gypsum Clinker Mill Raw Materials Gas Water Panoramic view of Ichihara Ecocement plant Gas treatment 34m Bag filter Heavy metal refining process Flue gas cooling tower Homogenizing tank Rotary kiln Fly ash tank Raw mat. mill Administrative office & bottom ash storage facilities Rotary dryer CEMENT PRODUCTION (17) Ichihara Ecocement Corporation (Rotary kiln) 366m 80m Lot area; 16,700m 2 58m Ecocement tank 5

6 CEMENT PRODUCTION (18) Applications of Ecocement to various concrete products Application for construction Application for construction Application for construction External wall Concrete block Concrete roof ENVIRONMENTAL ASPECT OF AGGREGATE PRODUCTION Application for civil works Application for civil works Application for civil works Inter rocking block Concrete block Marine product AGGREGATE PRODUCTION (1) Changes in aggregate production Production (million t) Crushed Stone River Gravel Pit Gravel Hill Gravel Sea Gravel Good quality river sand and river gravel have become depleted 949 million tons in 1990 Crushed stone and Crushed/pit sand have become major Causing exposure of bedrock on the bottom of the sea erosion of embankments endangering sand spits and fishing grounds AGGREGATE PRODUCTION (2) 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 PRODUCTION (3), 70% by volume of concrete, anticipated as a recipient of waste and byproducts from other industries CONCRETE PRODUCTION (1) Changes in concrete production million tons in 1990 Type Blast Furnace Slag Ferronickel Slag Copper Slag Electric Arc Furnace Oxidizing Slag Molten Slag Fly Ash Calcined Lightweight Standard JIS A JIS A JIS A JIS A JIS A 5031 Production and Waste (million t) Concrete Production decrease due to reductions in investment in new construction of buildings and civil structures Concrete Waste Concrete Waste from Buildings Concrete Waste from Civil Structures Year 6

7 CONCRETE PRODUCTION (2) Waste and byproducts generated from RMC plants Returned concrete from 1m 3 of RMC : m 3 Sludge cake resulting from 1m 3 of RMC : 5.88 kg CONCRETE RECYCLING Returned Concrete Mixer Agitator Truck Washing Water Waste Recovered Water Supernatant Water Sludge Water Sludge Solid Sludge Cake Final Disposal Coarse Fine Mixing Water Road Subbase CONCRETE RECYCLING (1) Recycle ratio of demolished concrete 年度 年度 年度 Effort by the Ministry of Construction Recycling Plan 21 Construction Recycling Promotion Plan 97 Reuse 再利用 Disposal 処分 For road bottoming materials For mechanical 0 stabilization materials Emission コンクリート塊排出量 of Concrete Lumps ( 万 (million t) t) CONCRETE RECYCLING (2) 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 CONCRETE RECYCLING (3) Recycle in Apartment Complex Demolished Building Sound-proof Wall Recycle Plant Crusher Sieve Backfilling 40-0mm 60-20mm Gravity Retaining Wall Concrete Pavement Powder Foundation Basement Road Subbase Improvement Packing Packing CONCRETE RECYCLING (4) Changes in concrete production Production and Waste (million t) Concrete Production decrease due to reductions in investment in new construction of buildings and civil structures 600 million tons Premature in 1990 deterioration Ends of their service lives Demolished Concrete Waste Concrete Waste from Buildings Concrete Waste from Civil Structures Year 7

8 CONCRETE RECYCLING (5) 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 CONCRETE RECYCLING (6) Recycling process of demolished concrete lumps Impact Crusher Vibratory Sieves Road Subbase, Backfill Low Quality Recycled Coarse Demolished Concrete Lumps Vibratory Sieves Cone Crusher Vibratory Sieves Jaw Crusher Low Quality Recycled Fine High Quality Recycled Coarse Heating Tower Coarse Scrubber Fine Scrubber Vibratory Sieves High Quality Recycled Fine (a) Road Subbase (b) Low Quality Recycled (c) High Quality Recycled Powder CONCRETE RECYCLING (7) 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 CONCRETE RECYCLING (8) Today s conventional concrete recycling Roadbed material for concrete excluding structural use CONCRETE RECYCLING (9) 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 CONCRETE RECYCLING (10) Quality and recovery percentage of recycled aggregate Water Absorption (%) 5-10mm not less than 10mm Recovery Percentage (%) Recycled Fine Recycled Coarse Size of Supplied Concrete Lumps Gravel Sand Powder Cement Paste No 1st 2nd 3rd Number of Crushing Treatment No 1st 2nd 3rd Original Concrete Crushing Treatment 8

9 CONCRETE RECYCLING (11) Efficient equipment for producing high quality recycled aggregate (1) Heated scrubbing CONCRETE RECYCLING (12) Heated scrubbing Heating Device Filled with Concrete Lumps Recovery of Coarse Recovery of Fine Bug Filter Heating at 300 C Rubbing process Sieve Tube Mill Tube Mill Fine Coarse Fine Powder Concrete rubble Weakening of hardened cement paste Removal of powdered cement hydrate Heated scrubbing CONCRETE RECYCLING (14) Dart Collector Powder Storage Tank Classifier Recycled structural aggregates & by-product powder Coarse Mill Recycled Coarse Heating Tower Recycled Fine Input Hopper Fine Mill CONCRETE RECYCLING (15) Quality of Recycled s CONCRETE RECYCLING (16) An Example of Application 14 Absorption (%) Recycled Fine/ Former systems Recycled Coarse/ Former systems Coarse & fine/ CLC system Virgin aggregate Oven-dry density (g/cm 3 ) Structure A : Place:Chofu city, Tokyo Year of completion: 1960 Structure B : Place:Kitakyushu city Year of completion: 1988 Acoustic Laboratory Construction period:11/2000-9/2001 Place:Koto-ku, Tokyo Structure:Reinforced concrete structure, three levels above the ground Building area:363.41m 2 Total floor area:667.75m 2 9

10 CONCRETE RECYCLING (17) An Example of Application CONCRETE RECYCLING (18) An Example of Application Concrete plant Recycled aggregate plant CONCRETE RECYCLING (19) Efficient equipment for producing high quality recycled aggregate (2) Mechanical scrubbing-1 (eccentric tubular type) Concrete Lumps Mechanical scrubbing-1 (eccentric tubular type) Eccentric Tubular Mill Scrubbing External Cylinder Motor Recovery Transmission Gear Mechanical scrubbing-1 (eccentric tubular type) Mechanical scrubbing-1 (eccentric tubular type) 1st sieve 2nd sieve Crushed Concrete lump Eccentric rotor device After the rotor device Product 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 ) 10

11 CONCRETE RECYCLING (23) Efficient equipment for producing high quality recycled aggregate (3) Mechanical scrubbing-2 (screw type) CONCRETE RECYCLING (24) Efficient equipment for producing high quality recycled aggregate (3) Mechanical scrubbing-2 (screw type) Cylinder Hollow Input Middle Cone Ejection Cone Rotary Blade Outlet CONCRETE RECYCLING (25) Efficient equipment for producing high quality recycled aggregate (4) Wet scrubbing and gravity classification Concrete Lumps CONCRETE RECYCLING (26) Efficient equipment for producing high quality recycled aggregate (4) Wet scrubbing and gravity classification Low Density Zone Water Level Supply Drum Rods Exit High Density Zone Water Level Range in Air Chamber Recycled with Low Density Recycled with High Density CONCRETE RECYCLING (27) Political Aspects Former Prime Minister, Junichiro Koizumi Why concrete is not recycled into concrete? Government official It is because there is no industrial standard. The Manifesto of the Democratic Party of Japan (opposition party) From Concrete to People, People, People suffered a crushing defeat in the general election CONCRETE RECYCLING (28) Japan industrial standards for recycled aggregate JIS A 5021 (March 2005) Recycled aggregate for concrete - Class H JIS A 5022 (March 2006) Recycled concrete using recycled aggregate Class M JIS A 5023 (March 2007) Recycled concrete using recycled aggregate Class L 11

12 Specified values of recycled aggregate in JIS Oven-dry density (g/cm 3 ) Water Absorption (%) Material passing 75 μm sieve (%) CONCRETE RECYCLING (29) Class - H Coarse Fine not less than 2.5 than 3.0 than 1.0 not less than 2.5 than 3.5 than 7.0 Class - M Coarse Fine not less than 2.3 than 5.0 than 1.5 not less than 2.2 than 7.0 than 7.0 Class - L Coarse Fine - than 7.0 than than 13.0 than 10.0 Application of recycled aggregate Class - H Class - M Class - L CONCRETE RECYCLING (30) Scope of application No limitations are put on the type and segment for concrete and structures with a nominal strength of 45MPa or less Members not subjected to drying or freezingand-thawing action, such as piles, underground beam, and concrete filled in steel tubes Backfill concrete, blinding concrete, and leveling concrete CONCRETE RECYCLING (31) Limits of Amount of Deleterious Substances for RA-H Category A B C D E F Deleterious substances Tile, Brick, Ceramics, Asphalt concrete Glass Plaster Inorganic substances other than plaster Plastics Wood, Paper, Asphalt Total Limits (mass%) CONCRETE RECYCLING (32) Large amount of by-product powders Resulting from production of high quality recycled aggregate Possible uses Addition to road bottoming Cement material CO Concrete addition Asphalt 2 -uptake filler Re Ground Re-absorption improving of material 30% of the total CO 2 emission Inorganic from cement board production material Demands Quality stabilization Reduction of quality control cost CONCRETE RECYCLING (33) Raw material of cement CONCRETE RECYCLING (34) Recyclable concrete like steel and aluminum Production process of concrete Conventional downstream approach focusing on Cost reduction Efficiency in production New production system incorporating upstream (inverse) processes in consideration of recyclability Ground improvement 12

13 CONCRETE RECYCLING (35) Conventional Material Flow of Concrete Recycling environmental disruption waste emissions (concrete rubble,asphalt concrete rubble,mixed rubble) demolition thermal energy compressive crush use and managenment Loop3 heating Loop2 Loop1 impact crush friction crush rubbling crush sieving demolition sieving subbase materials demolition Inspection non-structural structural aggregate Structural Concrete aggregate Non-structural Concrete compressive crush compressive crush impact crush sieving waste emissions (mixed rubble) CONCRETE RECYCLING (36) 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. Subbase Materials cement and original aggregate Production of Structural Concrete Loop 1 (Target : Structural Concrete) Loop 2 (Target : Non-structural Concrete) Loop 3 (Target : Sub-base Materials) environmental disruption CONCRETE RECYCLING (37) Completely recyclable concrete (CRC) Cement recovery type CRC CONCRETE RECYCLING (38) Completely recyclable concrete (CRC) Cement recovery type CRC Precast Concrete Foundations Made from CRC in Kita-kyusyu Perfect Recycle House in Kita-kyusyu CONCRETE RECYCLING (39) Completely recyclable concrete (CRC) 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. CONCRETE RECYCLING (40) Completely recyclable concrete (CRC) 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. 13

14 CONCRETE RECYCLING (41) Resource flow in real society CONCRETE RECYCLING (42) After 100 years After 50 years Present Final disposal area Road One flow affects another flow. Intermediate treatment facility Total impact in the whole society should be reduced. Structure Ready-mixed concrete plant Material plant Material flow should be further optimized in cooperation with other industries as part of the resource recycling of society as a whole, reflecting back on the abundant resource consumption of concrete and the long service lives of buildings and civil structures. CONCRETE RECYCLING (43) Future system for concrete recycling Recycling technology should fulfill the following principles. Recycling should be of high quality. Recycled products are not marketable unless they are of a quality that satisfies users. Recycling should be repeatable. If a recycled product has to be dumped in a landfill after use with no chance of recycling, then the recycling is no better than producing waste of the following generation. Assignment 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 s presentation file at tokyo.ac.jp/class_info/index.html 14