Environmental Benefits of Using Recycled Materials...Nov 01, 2016 · Recycled Materials Resource...

Recycled Materials

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Recycled Materials

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Environmental Benefits of

Using Recycled Materials

Recycled Materials Resource Center

University of Wisconsin-Madison

Angela Pakes Ahlman, P.E., LEED AP

Tuncer B. Edil, P.E., D.PG.

Erik Elliot and Andrew Baker

Recycled Materials

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11/9/2016Recycled Materials Resource Center

University of Wisconsin-Madison4

Recycled Materials Resource Center

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

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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?

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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

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?????

Life Cycle

Assessment

Life Cycle

Cost

Analysis

Quantifying Sustainability

11/9/2016

Recycled Materials

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Pavement Life-Cycle

Materials Construction Use MaintenanceEnd of

Life

Extraction

Production

Transport

Traffic Delay

Equipment

Rolling

Resistance

Traffic Delay

Production

Transport

Salvage

Transport

Courtesy NCAT

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Calculating LCA vs LCCA: Materials

• Life Cycle Cost Analysis

• How much does it cost to

buy the asphalt and the

aggregate and produce a

mixture?

• Life Cycle Analysis

• How much energy is

required to extract,

process, and transport

aggregate and asphalt?

• How much C02e is

produced during this

process?

• How much energy is

used and C02e is

produced at the plant?

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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

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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.

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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

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How Are We Doing?

19

0 2 4 6

Steel Reinforcement

Microsilica

Glass Beads

By-Product Lime

Steel Slag

Blast Furnace Slag

Rubber

RCA

RAS

RAP

Fly Ash

Number of States

1.741.81

0.630.58

1.89

1.05

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

To

ns o

f R

ecycle

d M

ate

ria

ls (

Mill

ion

s)

Tons (Millions)

Recycled Materials

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2013 Statewide Data:

WisDOT Recycled Material Profile

Total tons of recycled

material: 1,894,542

RAP in HMA28%

RAP in Base17%RAS

2%

RCA50%

Fly Ash3%

Recycled Materials

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MnDOT Recycled Material Profile

Total tons of recycled

material: 631,063

RAP64%

RCA31%

Fly Ash5%

Recycled Materials

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IDOT Recycled Material Profile

Total tons of

recycled material:

1,807,298

Steel Slag4.8%

Glass Beads0.3%

Ground Granulated Blast Furnace Slag

0.8%

Microsilica0.0004%

RAP54.3%

RAS2.2%

RCA27.7%

Fly Ash4.5%

Crumb Rubber5.3%

Recycled Materials

Resource Center 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)

82%

97%

85%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Energy (TJ) Water consumption(kg)

CO2 (Mg)

Environmental Impact Percent Reduction

Recycled Materials

Resource Center Quantitative Impact

6,390

1,180

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

Virgin Recycled

Energ

y (

TJ)

Energy

1,990

590

500

1,000

1,500

2,000

2,500

Virgin Recycled

Wa

ter

(Mg

)

Water Consumption

355,000

52,600

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

Virgin Recycled

CO

2 (

Mg)

CO2 Emissions

Recycled Materials

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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 CO2

Equates to:

• Energy consumption of 110,000 U.S. households annually

• 9,300 bathtubs of water ~ 70 Olympic-sized swimming pools

• CO2 emissions produced by 58,000 cars annually

Recycled Materials

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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.

Recycled Materials

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Case Study:

Interstate 94 Reconstruction



Kenosha County, Wisconsin

Recycled Materials

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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



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Schematic of Reconstruction

• Reconstruction

included:

• Mainline

• 4 Ramps

• STH 142

• Material quantities

calculated from

design plans



12” Portland Cement Concrete (PCC):

~32,000 CY

• 30% of cementitious material is fly ash

3” Asphalt base (mainline only): ~5,700 CY

Embankment: ~235,000 CY

• 70% bottom ash

• 5% foundry sand

• 25% native clays

13” Subbase: ~39,000 CY

• 40% Recycled concrete

aggregate (RCA)

6” Aggregate Base: ~19,000 CY

• 55% Recycled asphalt pavement (RAP)

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Results: BE2ST-In-Highways



Environmental Criteria Virgin Recycled Savings % Reduction

Energy Use (GJ) 195,000 124,000 71,000 37%

Water Consumption (kg) 52,900 39,800 13,100 25%

CO2 Emissions (Mg) 13,100 7,930 5,170 39%

SCC $806,000 $489,000 $317,000 39%

Hazardous Waste (kg) 824,000 604,000 220,000 27%

Recycling Virgin Recycled % Material Recycled

In Situ Recycling (CY) 0 24,960 7%

Total Recycling (CY) 0 202,200 57%

Recycled Materials

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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

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Case Study:

Beltline Highway Reconstruction



Dane County, Wisconsin

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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

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Beltline Highway



78% asphalt8%RAP, 14%RAS

Recycled Materials

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Data Collection Methodology Comparison

• Two data collection

methodologies

1. Designed Method -

Material quantities

estimated from pre-

construction 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)

Co

ncre

te

Cement 2,453 3,106

Fly ash 936 742

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 31,197H

MA

RAP binder 4 14

RAS binder 20 40

Asphalt binder 73 296

FRAP 269 516

RAS 58 114

HMA aggregate 1,588 2,216

HMA total 2,022 3,181

Ba

se

s

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



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LCA Results: PaLATE Impact % Reductions



17%

15%

17%

5%

21%

1%

4%

9%

11%

13%13%

12%12%

2%

24%

1%2%

5%

8% 8%

0%

5%

10%

15%

20%

25%

Energy Water CO2 NOx PM10 SO2 CO Hg Pb HazWaste

Designed Constructed

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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

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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

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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: www.rmrc.wisc.edu



Recycled Materials

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Download file

Download User

Manual

Recycled Materials

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Recycled Materials

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Enter bid

item

quantity

Enter % of

recycled

material

Recycled Materials

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• 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

Looking Ahead

Recycled Materials

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• Cost – Effective

• Flexible

• Feasible > 30m

• Eliminates space and material

61

Recycled Materials for MSE Wall Backfill

Recycled Materials

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Recycled Materials Webmap Tool

Recycled Materials

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Leaching of Alkaline Substances and Heavy

Metals from RCA Used as Unbound Base Course

11/9/2016

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

http://www.oregrinder.com/

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Environmental Issues

• High Alkaline Leachate

- Cement-based material

- Wide pH range (7.5 to 13) in field studies

• Leaching of Heavy Metals

Problem Statement

Iowa DOT (1999)

Recycled Materials

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Recycled Materials

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Bharat Madras Natarajan

Andrew Baker

Eleanor Bloom

Erik Elliot

Aaron Canton

Kelly del Ponte

Greg Horstmeier

[email protected]

www.RMRC.wisc.edu

Thank you!

Questions?

mailto:[email protected]

Recycled Materials

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SUPPLEMENTAL SLIDES



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