Evaluation of the Effect of Recycled

Asphalt Shingles on Ontario Hot Mix

Professor Susan Tighe, Ph.D, P.Eng

Canada Research Chair, Norman W. McLeod Professor

Director, Centre for Pavement and Transportation Technology

http://www.civil.uwaterloo.ca/CPATT/

Shirley Ddamba, Riyad UL-Islam

Ryan Essex

Narayan Hanasage, Trevor Moore

Jean Martin Croteau

Outline of Presentation

• Introduction/Project Objectives

• Research Methodology

• Background

• Field Section Locations Under Study

• Laboratory Testing and Performance Evaluation

• Field Performance Evaluation

• Life Cycle Assessment using PaLATE – Environmental Assessment and LCCA – Economic Assessment

• Closing Thoughts

Sustainable Transportation

Pavement Design and

Management

Material Use and Recycling

Traffic Planning

Public TransitAlignments

Land Use and Development

Walkways, Bikeways, &

Parkways

Sustainable pavement is a subset of sustainable transportation

Main focus on Pavement Design and Management; and Material Use and Recycling

Introduction

• 1.5 million tonnes of roofing

asphalt shingles produced

annually

• 90% end up in landfills

• Increased asphalt cement cost

• Innovations in recycling

• Potential to use in Ontario mixes

Introduction

Research Objectives

• Evaluate pavement performance

• Laboratory Testing - freeze-thaw cycle of test

Specimens and Visual Assessment of the Specimens

such as pavement distresses.

• Field test section (CPATT Test Track and Three

Residential Streets in Town of Markham, Ontario)

• Carry out Life-Cycle Assessment using LCCA and

PaLATE of using RAS in Ontario HMA pavements.

Recycled Asphalt Shingles

• RAS contains high quality manufactured

material, 70% of which pass sieve #200

• RAS consists of two types:

Manufactured Roofing Asphalt Shingle

Waste

Demolished/Tear-off roofing asphalt

shingles (also referred to as Post-

Consumer)

Feed Hopper

Horizontal ConveyerRemove Large Contaminants

Hammer Mill

Screen Deck

Removal Nails (Electro-Magnet)

Close Up Manufactured Shingles

Recycled Asphalt Shingles• Environmental:

• RAS in new products reduces the negative environmental impacts associated with the extraction, transportation and processing of virgin materials

• Conservation of landfill spaces - diverting non-degradable material

• Reduces Green House Gases (GHG)

• All material is recycled

• Economic:

• Reduces manufacturers and consumer costs due to reduced HMA production and contractor’s disposal fees respectively.

Recycled Asphalt Shingles

• Pavement:

• Asphalt shingle binds the crushed stone granular together leading to effective dust control.

• Reinforcement from fibers improves shear resistance to pavement cracking.

• Shingle fibers and increased binder stiffness results in improvement of rutting and shoving resistance.

Historical Usage:Recycled Asphalt Shingles

• Past 20 years, manufactured roofing asphalt shingles have been under study and used in HMA pavements in the US;

• MnDOT recommends the use of 3% - 5% RAS in HMA

• Canada, the concept is still in its early stages;

• 1995, Highway 86, Waterloo, Ontario – 3% Manufactured Shingle modifier.

• 2006, CPATT with public and private partners embarked on study to assess the effect of RAS on HL8 binder course. HMA mixture containing 1.4% RAS and 20% RAP exhibited best overall performance.

Field Test SectionsCPATT Test Track

420m HL3 1.5% RAS and13.5% RAP section over 20% RAP in HL8,

South-East corner of Regional Municipality of Waterloo’s Waste Management Facility

CPATT Test Track

Town of Markham;

Site 1: Ida Street (HL3 1.5% RAS and13.5% RAP)

Site 2: Paul Street and Vintage Lane (SP12.5 FC1 3.5% RAS)

Site 3: Thornhill Summit Drive (SP12.5 FC1 3.5% RAS)

Field Test Sections

Laboratory Testing

• Surface Layer

– Mix 1 – Hot Laid 3 (HL3) with 1.5 percent RAS and 13.5 percent RAP

– Mix 2 – Superpave 12.5 (SP 12.5) with FC1 3 percent RAS and 17 percent RAP

– Mix 3 – Superpave 12.5 (SP 12.5) FC2 with 3 percent RAS and 12 percent RAP

– Mix 4 – Superpave 12.5 (SP 12.5) FC2 with 6 percent RAS

• Base Layer

– Mix 5 – Superpave 19 (SP 19) with 3 percent RAS and 25 percent RAP

– Mix 6 – Superpave 19 (SP 19) with 3 percent RAS

– Comparison and Conventional HL3

Laboratory Testing• Preparing asphalt

specimens using Superpave Gyratory Compactor

• Initial asphalt Specimens Testing– Physical properties and

surface texture

– Friction testing using British Pendulum Tester (BPT)

• First and second set of freeze-thaw cycles

• Final specimen testing

Compacted Specimen

Diameter = 150mmHeight = 71-76mm

Gyratory

Mould

Superpave

Gyratory Compactor

Laboratory Testing• Height and diameter of each sample was given by Superpave Gyratory

Compactor

• Determination of Percent Air Voids

• Bulk Relative Density (BRD) – AASHTO Designation T 166-07

• After freeze-thaw cycling there was significant difference in mass and height of the specimens while no significant change in diameter was observed

Laboratory Testing: Surface Texture Testing

• Sand Patch Method (ASTM E 965-96)

Surface Texture Evaluation

First Cycle: no statistical

difference in pavement

surface texture

Second Cycle: a significant

change in texture as

expected with aging.

However, the Specimens

exhibited no significant

signs of distresses

Mix DescriptionSlab

Number

Initial MTD

(mm)

1st Set of

Cycles MTD

(mm)

2nd Set of

Cycles MTD

(mm)

A 0.05 0.04 0.03

B 0.05 0.04 0.03

C 0.04 0.04 0.04

A 0.04 0.03 0.03

B 0.04 0.03 0.03

C 0.04 0.04 0.03

A 0.06 0.05 0.07

B 0.08 0.07 0.05

C 0.05 0.04 0.05

A 0.06 0.07 0.07

B 0.05 0.05 0.05

C 0.07 0.06 0.07

A 0.04 0.04 0.03

B 0.04 0.04 0.03

C 0.04 0.03 0.03

A 0.05 0.05 0.04

B 0.04 0.04 0.03

C 0.04 0.04 0.03

Mix 6: SP 19 6% RAS

Mix 5: SP 19 3% RAS and

25%RAP

Mix 2: SP12.5 FC1 3% RAS

and 17% RAP

Mix 4: SP12.5 FC2 6% RAS

Mix 3: SP12.5 FC2 3% RAS

and 12% RAP

Mix 1: HL3 1.5% RAS and

13.5% RAP

Laboratory Testing: Skid Resistance Testing

• British Pendulum Tester (ASTM E 303-93)

Skid Resistance Evaluation

Strong evidence of change in skid resistance properties among the mixes (samples).

All specimens were in satisfactory condition for all condition except the severe conditions.

Mix 3: SP19 3% RAS and 25% RAP, had best skid resistance properties.

BPN SN BPN SN BPN SN

A 43 27 58 40 42 26

B 47 31 56 39 42 27

C 59 41 56 38 41 26

A 44 28 51 34 39 24

B 46 30 51 34 41 25

C 51 34 53 36 38 23

A 48 31 52 35 39 24

B 47 31 52 35 38 23

C 56 39 49 33 42 27

A 53 36 53 36 42 26

B 51 35 55 38 38 23

C 53 36 50 33 40 24

A 44 29 51 34 39 24

B 48 32 54 37 40 25

C 45 29 52 35 45 29

A 51 34 54 37 39 24

B 47 31 54 37 41 26

C 45 29 52 35 39 24

Mix 2: SP12.5 FC1 with 3%

RAS and 17%RAP

Mix 3: SP12.5 FC2 with 3%

RAS and 12% RAP

Mix 4: SP12.5 FC2 with 6%

RAS

Mix 5: SP 19 with 3% RAS

and 25%RAP

Mix 6: SP 19 with 6% RAS

Mix DescriptionSpecimen

No.

Initial 1st Set of Cycles 2nd Set of Cycles

Mix 1: HL3 with 1.5%

Recycled Asphalt Shingles

(RAS) and 13.5% Reclaimed

Asphalt Pavement (RAP)

Field Performance Evaluation: CPATT Test Track

Ravelling

Aggregate

Loss

Pothole

Overall; the pavement was observed to be in excellent condition

• Pavement Distress Survey according to MTO guidelines

Field Performance Evaluation: CPATT Test Track

• Non-destructive test was carried using a Portable Falling Weight Deflectometer (PFWD) - Dynatest 3031

Comparison of Deflection Measurements

70

90

110

130

150

170

190

210

900 950 1000 1050 1100 1150

Chainage (m)

Def

lect

ion

(M

icro

ns)

Loaded Lane (2011) Unloaded Lane (2011) Loaded Lane (2010) Unloaded Lane (2010)

Field Performance Evaluation: CPATT Test Track

• Friction Testing using BPT:• The BPN/SN indicated

the RAS section was still in good safe condition to support the traffic loading it carries.

• BPN > 45, which is acceptable for heavy travelled roads as supported by SN > 40

Field Performance Evaluation: Town of Markham

• Pavement Surface Distress Survey:

– Residential Streets were constructed in 2007, support low traffic volume

– Site 1 exhibited some cracking and aggregate pop-outs

– Site 2 and Site 3 did not exhibit significant visual signs of distresses and were in excellent conditions

– Storm management systems were still in excellent condition with no blockage

– Overall all, despite no maintenance on the streets, they are still in good condition

Site 1: Ida Street

Field Performance Evaluation: Town of Markham

Site 2: Paul Street and Vintage Lane

Site 3: ThornhillSummit Drive

Environmental Impact Assessment: PaLATE• Pavement Life Cycle Assessment Tool for Environment and Economic Effect

(PaLATE)

• Life-cycle analysis tool that evaluates environmental and economic information to evaluate the use of different materials

Design Worksheet

Environmental Impact Assessment: PaLATE

• RAS is not accounted for in PaLATE, the AC from RAS is assumed to contribute 30% to virgin AC and also contributes to aggregates required

• Total RAS was added to RAP

Initial Construction Worksheet

Environmental Impact Assessment: PaLATE

Consumption savings – Control Mix

Environmental Impact Assessment: PaLATE

Environmental Savings – Control Mix

Economic Assessment - LCCA

• Life-Cycle Cost Analysis (LCCA) evaluates long-term economic

implications of pavement decisions

• Identify lowest cost alternative that accomplishes the project

objectives without compromising pavement performance

• Three discount rates (3%, 5% and 7%) have been examined

Economic Assessment - LCCAMix Description

PWC at 5%

Discount

Comparison

(%)

Control Mix: Conventional HL3 1,015,286.69$

Mix 1: HL3 1.5% RAS 13.5% RAP 1,053,453.81$ 3.6%

Mix 2: SP 12.5 FC1 3% RAS, 17% RAP 1,069,018.67$ 5.0%

Mix 3: SP 12.5 FC2 3% RAS, 12% RAP 1,090,660.48$ 6.9%

Mix 4: SP 12.5 FC2 6% RAS 1,068,187.96$ 5.0%

Mix 5: SP 19E 3% RAS, 25% RAP 937,301.86$ -8.3%

Mix 6: SP 19E 6% RAS 959,728.22$ -5.8%

Mix DescriptionPWC at 7%

Discount

Comparison

(%)

Control: Conventional HL3 1,011,092.13$

Mix 1: HL3 1.5% RAS 13.5% RAP 1,045,402.14$ 3.3%

Mix 2: SP12.5 FC1 3% RAS, 17% RAP 1,056,537.56$ 4.3%

Mix 3: SP12.5 FC2 3% RAS, 12% RAP 1,076,801.44$ 6.1%

Mix 4: SP12.5 FC2 6% RAS 1,066,843.15$ 5.2%

Mix 5: SP19E 3% RAS, 25% RAP 932,602.99$ -8.4%

Mix 6: SP19E 6% RAS 953,836.98$ -6.0%

• Comparison of Present Worth Cost of Design Mixes to Conventional HL3

Conclusions• Laboratory Testing (Freeze-Thaw Cycling and Surface Distress Evaluation)

showed Mix 5: SP19 3% RAS and 25% RAP best to adapt to climatic changes and maintain highest skid resistance

• Field Evaluations indicated to be in good condition with no significant visible signs of distress. CPATT Test Track, Paul Street and Vintage Lane, and Thornhill Summit Drive had the better performance than Ida Street.

• Life-Cycle Assessment indicated Mix 5: SP19 3% RAS and 25% RAP was the most optimal sustainable and economical HMA mix

• Overall; Mix 5: SP19 3% RAS and 25% RAP is the optimal design mix; RAS can be a useful additive to HMA mixtures if engineered properly into the mix.

Next Steps• Verification long-term performance of pavements designed with RAS

• Investigate of climate changes for various percentages of RAS after 5 to 10

years in service

• Examine recyclability of HMA pavements containing RAS

• Establish standard mix designs for HMA pavements containing varying

percentages of RAS

• Study RAP on RAS in various HMA mixtures

Questions/Comments

Susan L. Tighe, PhD, PEng

sltighe@uwaterloo.ca or 519-888-4567 x 33152

Ryan Essex, MBA, PEng

ryane@millergroup.ca or 905-726-9518