Putting Earth Day into Practice Every Day: Life Cycle Cost Analysis and the Environment

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Putting Earth Day into Practice Every Day 
Life Cycle Cost Analysisand the Environment
Dr. Kevin Gardner Co-Director, RMRC April 22nd,
2008
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Objective

• Develop economic evaluation tools/software to
  assess short-term costs, life-cycle costs and
  life cycle impacts of using recycled materials in
  transportation infrastructure.
• Through outreach get these tools used and lessons
  learned to the community.
• Understand environmental behavior of recycled
  materials and provide clear guidance on
  appropriate use and potential risks.

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Life Cycle Assessment

• A tool that can help with understanding the
  broader impacts of a material or process.
• What are environmental costs and benefits of
  using recycled materials?
• Are there additional environmental or societal
  benefits that off-set potential site-specific
  risks?

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Modeling Tools

• Pavement Life Cycle Assessment Tool for
  Environmental and Economic Effects (PaLATE)
• Materials, design parameters, equipment,
  maintenance and cost inputs
• Provides full life cycle costs and environmental
  assessment.
• Macro-scale analysis based on Dept of Commerce
  census data
• Provides estimates of life cycle air emissions,
  contaminant releases, water and energy
  consumption and cancerous and non-cancerous human
  toxicity potentials
• Provides estimates of difference in impact due to
  transportation distance or different type of
  construction materials (virgin vs recycled)

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Case Study 1

• NH DOT Construction Project in central NH
• Portion of project will utilize rubblization of
  an existing concrete roadway
• Investigate alternative materials and compare
  life-cycle costs and life cycle impacts
  (environmental effects)
• Data from DOT engineers put into PaLATE small
  investment in time.

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NH DOT Case Study

• Initial Construction
• Option 1
• Mill off the existing Pavement
• Rubblize (Recycle) Concrete / Cover with
  (Recycled) Pavement Millings
• Widen with Virgin Materials
• Pave with 3.5 on New Hot Mix Asphalt
• Option 2
• Remove Concrete Slab and landfill
• Construct 12 of Gravel Crushed Gravel full
  width
• Pave with 5.5 of New Hot Mix Asphalt

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NH DOT Case Study (cont)

• Maintenance Option 1
• Years 4 8 Crack Seal
• Year 12 Resurface 1 Wearing Course
• Years 16 20 Crack Seal
• Year 24 Resurface 1 Wearing Course
• Maintenance Option 2
• Year 1-11 nothing
• Year 12 Hot In-Place Recycling (HIPR)
• Year 13-23 nothing
• Year 24 HIPR

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Life Cycle Costs NH DOT Case Study
virgin
virgin
Recycled
Recycled
virgin
Recycled

• Initial Construction cost for rubblization is
  about half that of using virgin materials
• Maintenance cost of crack sealing resurfacing
  is about twice that of HIPR

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Case Study 2 Wisconsin

• University of Wisconsin Pilot Scale project
  located in Lodi, WI
• Roadway description
• 305 m length
• 10.4 m width pavement
• 13.4 m width base sub-base
• Materials
• Bottom ash
• Control crushed rock

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Scenario (2)

• Lysimeters underneath test sections collect
  leachate generated.
• Groundwater 5 m below sub-base
• Soil composition of site silty-loam (USGS
  reports)
• Material source distances
• 50 mi
• 100 mi
• Contaminants analyzed Cd, Cr, Se, Ag

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PaLATE Results (2)

• Impact ratio or except HTP Cancer
• HTP Cancer human toxicity potential due to
  cancer
• HTP Cancer Impact from bottom ash is higher
  than impact from crushed rock
• Transportation factor
• For all impact categories, except SO2,
  transportation distance affects impact
• NOX and HTP non-cancer, most affected by
  transportation distance.

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Modeling Tools (2)

• Hydrus 2D
• Finite element modeling program for simulating
  movement of water, heat, and multiple solutes in
  variably saturated media.
• Predicts local scale transport of contaminants
  from recycled materials to groundwater over
  several hundred years.

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Hydrus 2D Results

• Hydrus 2D simulation for transport of Cr from
  bottom ash in road sub-base to groundwater (5
  meter below recycled materials layer) over 200
  years.
• Assumes constant influx of contaminant into system

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Hydrus 2D Results (2)

• Hydrus 2D simulation for transport of Se from
  bottom ash in road sub-base to groundwater (5
  meter below recycled materials layer) over 200
  years
• Assumes constant influx of contaminant into system

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Hydrus Results (2)

• Leaching potential for Wisconsin roadway is
  higher than published leaching studies and for
  Cd, higher than MCL
• PaLATE results based on Morse et al (2001) data
  SPLP test results
• Hydrus2D predictions based on UWisc data
• PaLATE used materials potential leaching
  quantities in HTP cancer predictions
• Quantities reaching groundwater are significantly
  less than MCL as predicted by Hydrus2D

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Case Study Scenario (Pittsburgh)

• Divided PA DOT PGH region into 20 blocks.
• Identified highest road density locations.
• Sourced aggregate from virgin locations currently
  approved or IBPs from their location of
  generation.
• Analyzed life cycle impact from aggregates
  (virgin vs. industrial byproducts)

Aside we are developing a GIS-based tool that
will enable users to view recycled materials
sources on Google Earth with data layers
(material type, amounts, location, contact
information, etc.).
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Embodied Energy in Road (from aggregate only!)
Text
Note none of the analyses presented consider
impacts associated with separate
disposal/management of industrial byproducts
(that analysis is forthcoming).
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Impacts (person equivalents)
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Hey Pittsburgh Want to save 3 million?
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In Summary

• We can use recycled materials to help the Earth
  AND save money at the same time.
• There is still research and outreach work that
  needs to be done.
• What to do you think needs our attention?
• RMRC pooled fund study can be used to leverage
  research and outreach.