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Kendra A. Morrison, U.S. EPA Region 8 Analysis of Recycling Asphalt Shingles in Pavement Mixes from a Life Cycle Perspective.

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Presentation on theme: "Kendra A. Morrison, U.S. EPA Region 8 Analysis of Recycling Asphalt Shingles in Pavement Mixes from a Life Cycle Perspective."— Presentation transcript:

1 Kendra A. Morrison, U.S. EPA Region 8 Analysis of Recycling Asphalt Shingles in Pavement Mixes from a Life Cycle Perspective

2 WHY WAS THE STUDY CONDUCTED? Support the Colorado Roofs to Roads Initiative: Growing interests in EPA Region 8: CO, MT, ND, SD, UT, and WY Look at environmental benefits from recycling more holistically What we expect: Conservation of natural resources Save landfill space Decrease emissions of greenhouse gases (GHGs) and other releases/impacts Energy savings 2

3 LIFE CYCLE ASSESSMENT (LCA) BASED STUDY Environmental life cycle assessment is a quantitative accounting of the cumulative environmental impacts of a product or process across all stages of the life cycle 3

4 WHAT WAS THE GOAL? GOAL: To compare limited environmental inventory and impacts of seven (7) asphalt mixes with various percentages of reclaimed asphalt and recycled shingles to a baseline of virgin asphalt EPA’s analysis is only an initial, limited life cycle inventory and impact assessment 4

5 ABOUT REPORT AND KEY CONTENT Considers recovered materials and innovative technologies used in asphalt production Used regional characterization factors, where possible: (e.g. mix designs and distances to obtain materials and to transport pavement to the construction site) Inventory and impacts examined from material extraction to transport to the construction site: Avoided landfill impacts Greenhouse gas (GHG) emissions/Global Warming Potential (GWP) Criteria and other air pollutants Energy consumption and resource depletion are considered only for select stages in the life cycle 5

6 SCOPE AND PROCESS DESCRIPTION 6

7 WHERE WAS THE DATA COLLECTED FROM? Local asphalt producers – energy and materials, mix designs National Renewable Energy Laboratory’s U.S. Life Cycle Inventory Database – fuels, electricity, transportation, equipment and process emissions National Institute of Standards and Technology’s Building for Environmental and Economic Sustainability (BEES) tool – sand and aggregate data EPA’s Waste Reduction Model (WaRM) – GHG savings information Intergovernmental Panel on Climate Change (IPCC) – global warming potentials 7

8 MIX SCENARIOS Scenario Type of Mix Design Mix Referred To As 1 HMAVirgin Materials Virgin 2 HMAHot Mixed Reclaimed Asphalt Pavement (20%) 20% RAP 3 WMA Warm Mixed Reclaimed Asphalt Pavement (20%) WMA 20% RAP 4 HMA 20% Reclaimed Asphalt Pavement and 3% Recycled Asphalt Shingles 20% RAP-3% RAS 5 HMA 20% Reclaimed Asphalt Pavement and 5% Recycled Asphalt Shingles 20% RAP-5% RAS 6 HMA 20% Reclaimed Asphalt Pavement and 7% Recycled Asphalt Shingles 20% RAP-7% RAS 7 HMA 17% Reclaimed Asphalt Pavement and 3% Recycled Asphalt Shingles 17% RAP-3% RAS 8 HMA5% Recycled Asphalt Shingles 5% RAS 8

9 SOME KEY ASSUMPTIONS Virgin aggregate is transported 36 miles, while recycled materials are transported 9 miles. Transportation to the construction site is 30 miles for all asphalt mixes except WMA 20% RAP, which is assumed to be transported 60 miles. RAP contains 4% binder and RAS contains 24.3% binder by weight. All mixes require binder from the petroleum refiners, have the aggregates heated using natural gas, and are mixed in a drum plant. The physical activities associated with placing, maintaining, and removing of the pavements, as well as the emissions from those activities, are assumed to be similar across all scenarios. All asphalt mixes are able to perform under the road conditions for which they are designed. 9

10 10 RESULTS All results are reported with respect to the production of 1 short ton of asphalt transported to a road construction site.

11 ENERGY USE 11 Energy Consumption During Select Life Cycle Stages WMA 20% RAP = 12% energy reduction vs. HMA 20% RAP mix

12 RESOURCE DEPLETION Scenario Virgin Quantity (lb/short ton) Recycled Quantity (lb/short ton) Virgin 1, % RAP 1, WMA 20% RAP 1, % RAP-3% RAS 1, % RAP-5% RAS 1, % RAP-7% RAS 1, % RAP-3% RAS 1, % RAS 1, Quantities of Virgin and Recycled Aggregates

13 AVOIDED LANDFILL IMPACTS Scenario Mass Avoided (lbs/short ton) Volume Avoided (cubic yards/short ton) Virgin 00 20% RAP WMA 20% RAP % RAP-3% RAS % RAP-5% RAS % RAP-7% RAS % RAP-3% RAS % RAS Mass and Volume Reductions from Recycling RAS and RAP

14 GREENHOUSE GAS CREDIT FOR AVOIDED LANDFILL 14

15 GREENHOUSE EMISSIONS When transportation to the construction site is assumed to be 30 miles for all asphalt mixes, there is a 3% reduction in GHGs when switching from the 20% RAP to the WMA 20% RAP. When transportation to the construction site is assumed to be 60 miles for the WMA 20% RAP (30 miles for all other mixes), the WMA 20% RAP GHG emissions are 9% higher. 15

16 GLOBAL WARMING POTENTIAL 16

17 GLOBAL WARMING POTENTIAL Change (lbs CO₂e/short ton) 20% RAP WMA 20% RAP 20% RAP, 3% RAS 20% RAP, 5% RAS 20% RAP, 7% RAS 17% RAP, 3% RAS 5% RAS With no Landfill Credit %4%-10%-13%-16%-10%-6% With Landfill Credit %-6%-21%-25%-29%-19%-9% 17 = mix with greatest reduction = RAS mixes meeting CDOT specification

18 CRITERIA AND OTHER AIR POLLUTANTS 18

19 AIR POLLUTANTS BY PROCESS FOR 20% RAP-5% RAS MIX 19

20 CONCLUSIONS There are environmental benefits to the use of recycled asphalt shingles (RAS) in asphalt production for use in road construction. Larger reductions in impacts are seen when RAP is included over solely using RAS. The addition of RAP reduces the amount of virgin aggregate required which must be transported over a longer distance. Combining RAP and RAS diverts even larger volumes of material away from landfills, and these amounts are quantified in the study. 20

21 CONCLUSIONS The addition of RAS to pavement mixes that use RAP helps further increase environmental reductions relative to the baseline of using virgin asphalt. 21 Decreasing GWP as RAS Content Increases in HMA mixes

22 CONCLUSIONS Transport distances for aggregate and asphalt are both highly sensitive variables that can have large impacts on the total life cycle emissions. transportation distance for WMA from 30 to 60 miles raises the GHG emissions for transportation by 51% compared to the equivalent HMA case. The change is 19 lbs CO2e/short ton of asphalt, which is over 10% of the emissions considered in the study. 22 Asphalt Plant Aggregate Production Loader Roadway Construction

23 GOING FORWARD WITH RAS Asphalt shingles (and asphalt pavement) are 100% recyclable. Recycling saves landfill space Emissions of GHGs associated with operation and transportation to the landfill are avoided Upstream impacts from aggregate processing are mitigated Conservation of natural resources Reduction of environmental pollution from material extraction and processing GHG and other air emissions from transport are reduced due to less fuel consumption Valuable oil is reused and upstream air emissions are reduced Win / win when used responsibly 23

24 WHO CONTRIBUTED TO THE PEER REVIEWED REPORT? Peer consultation during development: Jarrett Welch – Brannon Sand & Gravel Co. Gary Stillmunkes – Asphalt Specialties Company Inc. William Turley – Construction Demolition & Recycling Association Dr. Howard Marks – National Asphalt Pavement Association Dr. Audrey Copeland – National Asphalt Pavement Association Peer reviewers of draft final report: Dr. Maryann Curran – U.S. EPA Office of Research and Development Marie Zanowick – U.S. EPA Region 8 Dr. Alberta Carpenter – National Renewable Energy Laboratory Dr. Arunprakash Karunanithi – University of Colorado Denver Victor (Lee) Gallivan – Federal Highway Administration 24

25 CONTACT INFORMATION AND REPORT Kendra A. Morrison U.S. EPA Region 8 (303) Report can be obtained from EPA Region 8’s website: recycling recycling Construction Demolition & Recycling Association (2013). C&D World. September/October, 6(5):


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