Environmental Benefits of Using Recycled Materials

Transcription

1 Environmental Benefits of Using Recycled Materials Recycled Materials University of Wisconsin-Madison Angela Pakes Ahlman, P.E., LEED AP Tuncer B. Edil, P.E., D.PG. Erik Elliot and Andrew Baker

2 Recycled Materials Recycled Materials in Roadways: Improving Sustainability, Quality and Service Life - Promote safe and wise use of recycled materials in construction of transportation infrastructure through education, technology transfer, and applied research. - Wise ensure that recycled material is suitable for highway environment and provide procedures for appropriate use. - Safe ensure material will not adversely impact environment or users. Recycled Materials University of Wisconsin-Madison 4

3 Current Practice - Various recycled materials and industrial byproducts are used in highway construction applications - Engineering properties and environmental suitability issues relevant to various applications, incorporated design guidelines and construction specifications - Benefits? Recycled Materials University of Wisconsin-Madison 10

4 So What s Missing? - Direct information on sustainability assessment characteristics - Tracking is a challenge - Cannot readily calculate the benefits accrued by substitution of these materials for conventional materials Recycled Materials University of Wisconsin-Madison 11

5 Quantifying Sustainability Life Cycle Cost Analysis????? Life Cycle Assessment

6 Pavement Life-Cycle Extraction Production Transport Traffic Delay Equipment Rolling Resistance Traffic Delay Production Transport Salvage Transport Materials Construction Use Maintenance End of Life Courtesy NCAT

7 Calculating LCA vs LCCA: Materials Life Cycle Analysis How much energy is required to extract, process, and transport aggregate and asphalt? How much C0 2e is produced during this process? How much energy is used and C0 2e is produced at the plant? Life Cycle Cost Analysis How much does it cost to buy the asphalt and the aggregate and produce a mixture?

8 DOT Statewide Use of Recycled Materials Material quantities estimated from designs and specifications for calendar/fiscal year of 2013 Unit cost of recycled materials determined by surveying providers and material associations in each member state Unit cost of virgin materials estimated using local construction costs as well as Engineering News- Record (ENR) price indices

9 Objectives State DOTs seeking a quantitative and transparent manner in which to clearly convey the benefits in using recycled materials. Adopt, improve and use a tool to calculate the life cycle benefits associated with incorporating these materials in highway construction. Develop fact sheets on recycled materials and industrial by-products being used in highway construction.

10 Common Recycled Materials Every participating state uses: 1. Reclaimed Asphalt Pavement (RAP) 2. Fly Ash Other common materials: 1. Reclaimed Asphalt Shingles (RAS) 2. Recycled Concrete Aggregate (RCA) 3. Crumb Rubber 4. Tire Derived Aggregate 5. Bottom Ash 6. Foundry Sand 7. Foundry Slag 8. Iron Slag

11 Tons of Recycled Materials (Millions) Recycled Materials How Are We Doing? Tons (Millions) Fly Ash RAP RAS RCA Rubber Blast Furnace Slag Steel Slag By-Product Lime 0.4 Glass Beads 0.2 Microsilica 0.0 Steel Reinforcement Number of States 19

12 2013 Statewide Data: WisDOT Recycled Material Profile Total tons of recycled material: 1,894,542 Fly Ash 3% RAP in HMA 28% RCA 50% RAS 2% RAP in Base 17%

13 2013 Statewide Data: MnDOT Recycled Material Profile Total tons of recycled material: 631,063 Fly Ash 5% RCA 31% RAP 64%

14 2013 Statewide Data: IDOT Recycled Material Profile Total tons of recycled material: 1,807,298 Crumb Rubber 5.3% Fly Ash 4.5% Steel Slag 4.8% Glass Beads Ground Granula 0.3% Blast Furnace S 0.8% Microsilica % RCA 27.7% RAP 54.3% RAS 2.2%

15 What s Our Impact? Recycled impact of total recycled material quantities tracked and reported by 6 DOTs in 2013 Reference impact of hypothetical, equivalent virgin material quantities (1:1 replacement) 90% of recycled material from existing pavement (RAP & RCA) 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Environmental Impact Percent Reduction 97% 82% Energy (TJ) Water consumption (kg) 85% CO2 (Mg)

16 CO2 (Mg) Energy (TJ) Water (Mg) Recycled Materials Quantitative Impact Energy Water Consumption 7,000 6,000 5,000 4,000 3,000 2,000 1, ,390 Virgin 1,180 Recycled 2,500 2,000 1,500 1, ,990 Virgin 59 Recycled CO 2 Emissions 400, , , , , , ,000 50, ,000 Virgin 52,600 Recycled

17 Total Environmental Savings Total estimated environmental savings across six DOTs: 4,500 TJ of energy 1.6 million kg of water 49,000 Mg of CO 2 Equates to: Energy consumption of 110,000 U.S. households annually 9,300 bathtubs of water ~ 70 Olympic-sized swimming pools CO 2 emissions produced by 58,000 cars annually

18 Key Takeaways RAP in HMA is the most widely used material and resulted in the greatest environmental savings Environmental and economic benefits are influenced by a combination of amount and type of recycled materials used Economic savings are dependent on local cost structure of the state in which materials are used Sustainability benefits of recycled materials: reduce energy, resource consumption, emissions & cost Create longer lasting infrastructure (not a linear landfill). Ensure equivalent or improved with field performance data.

19 Case Study: Interstate 94 Reconstruction Kenosha County, Wisconsin Recycled Materials University of Wisconsin-Madison 33

20 LCA/LCCA Goal Determine environmental and economic benefits of recycled materials in highway construction Analyze 1-mile stretch of I-94 North-South corridor in Kenosha County, WI Constructed in 2013 Expansion and full pavement reconstruction Targeted for unique use of recycled materials LCA and LCCA Data collected post-construction Recycled Materials University of Wisconsin-Madison 34

21 Schematic of Reconstruction 12 Portland Cement Concrete (PCC): ~32,000 CY 30% of cementitious material is fly ash 3 Asphalt base (mainline only): ~5,700 CY 6 Aggregate Base: ~19,000 CY 55% Recycled asphalt pavement (RAP) 13 Subbase: ~39,000 CY 40% Recycled concrete aggregate (RCA) Embankment: ~235,000 CY 70% bottom ash 5% foundry sand 25% native clays Reconstruction included: Mainline 4 Ramps STH 142 Material quantities calculated from design plans Recycled Materials University of Wisconsin-Madison 35

22 Results: BE 2 ST-In-Highways Environmental Criteria Virgin Recycled Savings % Reduction Energy Use (GJ) 195, ,000 71,000 37% Water Consumption (kg) 52,900 39,800 13,100 25% CO 2 Emissions (Mg) 13,100 7,930 5,170 39% SCC $806,000 $489,000 $317,000 39% Hazardous Waste (kg) 824, , ,000 27% Recycling Virgin Recycled % Material Recycled In Situ Recycling (CY) 0 24,960 7% Total Recycling (CY) 0 202,200 57% Recycled Materials University of Wisconsin-Madison 38

23 Key Takeaways Use of recycled material reduced environmental and economic impact of highway over lifetime Much of the economic and environmental benefits stem from use of bottom ash use what s locally available (fly ash, bottom ash, RAP, RCA) Estimated quantities led to some overgeneralizations and many assumptions on material use Seek to correct this by explicitly tracking material in future projects Recycled Materials University of Wisconsin-Madison 42

24 Case Study: Beltline Highway Reconstruction Dane County, Wisconsin Recycled Materials University of Wisconsin-Madison 43

25 Project Background Analyze 1.5-miles of Eastbound Beltline Highway Reconstruction 2 to 3 lane expansion and full reconstruction of the highway Typical recycled material use RAP, RAS, fly ash, RCA LCA and LCCA Data collected from designs and during construction Recycled Materials University of Wisconsin-Madison 44

26 Beltline Highway 8%RAP, 14%RAS 78% asphalt Recycled Materials University of Wisconsin-Madison 45

27 Bases HMA Concrete Recycled Materials Data Collection Methodology Comparison Two data collection methodologies 1. Designed Method - Material quantities estimated from preconstruction designs and average mix ratios 2. Constructed Method Material quantities explicitly tracked and collected during construction Summary of Initial Construction Material Quantities Material Designed (CY) Constructed (CY) Cement 2,453 3,106 Fly ash Slag 0 22 PCC aggregate 20,703 26,289 PCC mix water 3,560 4,575 Bridge concrete total 3,788 3,977 Pavement concrete total 23,865 31,197 RAP binder 4 14 RAS binder Asphalt binder FRAP RAS HMA aggregate 1,588 2,216 HMA total 2,022 3,181 On-site RAP 3,280 9,973 On-site RCA 3,246 9,870 Imported RCA 5,527 9,280 Imported virgin aggregate 1,595 3,933 Virgin subbase 9,130 11,823 RCA subbase 17,883 16,628 Recycled Materials University of Wisconsin-Madison 46

28 25% 20% 15% 10% 5% 0% LCA Results: PaLATE Impact % Reductions 17% 13% 15% 12% 17% 12% 5% 2% 21% 24% 1% 1% 4% 2% 9% 5% 11% 13% 8% 8% Energy Water CO2 NOx PM10 SO2 CO Hg Pb Haz Waste Designed Constructed Recycled Materials University of Wisconsin-Madison 49

29 Comparison Designed vs. Construction Method Design data over-generalizes the actual materials use Constructed data found greater material quantities, led to greater absolute environmental impacts Ave. difference between proposed design and constructed reductions was 9% SimaPro vs. PaLATE Tools predicted results within the same order of magnitude each data set Difficult to compare results between different LCA tools Different inventories, conversion methods, assessment methods Recycled Materials University of Wisconsin-Madison 54

30 Key Takeaways Constructed Method more accurate method for analyzing environmental and economic benefits Design Method acceptable method for estimating impacts If it is not feasible to explicitly track material use during construction, Design Method is acceptable alternative LCA tool matters less than data collection method Focus future effort on material tracking for LCAs and LCCAs when these issues are critical DOTs currently do not have a means of explicitly tracking recycled material use in projects Recycled Materials University of Wisconsin-Madison 55

31 RMRC Recycled Materials Tracking Tool Developed by the RMRC for DOTs to track the use of recycled material in specific construction projects Allows the materials engineers to track and organize quantities of recycled materials used in various project Available at the RMRC website: Recycled Materials University of Wisconsin-Madison 56

32 Download file Download User Manual Recycled Materials University of Wisconsin-Madison 57

33 Recycled Materials University of Wisconsin-Madison 58

34 Enter bid item quantity Enter % of recycled material Recycled Materials University of Wisconsin-Madison 59

35 Looking Ahead RMRC Executive Board is seeking new research ideas and partners with research ideas and funds for RMRC- 4G - TPF-5(362) State-Wide Life Cycle Benefits of Recycled Materials documentation and presentations to DOTs Phase II for Recycled Materials as Back Fill for Mechanically Stabilized Earth Walls installations and field testing Recycled Material Web Map: Connecting Consumers with Producers full scale launch Issues associated with high ph leachate from RCA and some fly ashes

36 Recycled Materials for MSE Wall Backfill Cost Effective Flexible Feasible > 30m Eliminates space and material 61

37 Recycled Materials Webmap Tool

38 Leaching of Alkaline Substances and Heavy Metals from RCA Used as Unbound Base Course Recycled Concrete Aggregate (RCA) Demolition of concrete pavement, bridge structures, roadway structures, airport runways Uses Infrastructure backfill; e.g., pavement base course Advantages Excellent mechanical properties Significant life-cycle benefits Widely available and used

39 Environmental Issues High Alkaline Leachate - Cement-based material Problem Statement - Wide ph range (7.5 to 13) in field studies Leaching of Heavy Metals Iowa DOT (1999)

40 Participating State DOTs

41 Recycled Materials Bharat Madras Natarajan Andrew Baker Eleanor Bloom Erik Elliot Aaron Canton Kelly del Ponte Greg Horstmeier Thank you! Questions?

42 SUPPLEMENTAL SLIDES Recycled Materials University of Wisconsin-Madison 72