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Stephen Steed Business Development, Coughlin Company Inc.

Controlling Quality - What Matters for Performance of

In-Place Recycling

41st annual Rocky Mountain Asphalt Conference

Denver, Co

What are the Keys to a Successful/Quality In-place Recycling Project?

• Proper Site Selection – Right Method Right Road

• Good Communication and Education Especially For Inexperienced Agencies

• Experienced ARRA Contractor

Quality Achieved at Each of Three Phases

• Before Design

• Before Construction

• During Construction

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QUALITY PHASE 1 BEFORE DESIGN

Making A Successful Project

• Analyze Existing Structure and/or Conditions

• Understand Causes for Distress or Need

• Analyze Geometric Profile of Road

• Consider any Drainage or Base Problems

• Determine the Feasible Treatment Options

• Select Best Materials & Methods

• Consider Most Cost Effective Use of Onsite Materials

• Use Engineered Design Approach

Process and Information for Selection of Treatment Option

Condition Survey of Roadway

Drill Core Samples or Depth checks

Use Falling Weight Deflectometer on projects

With Questionable Structural sections

Determine Cause of Pavement Distress

Functional Distress

Structural Distress

Cold In-Place Recycling

Reconstruction

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Asphalt In-place Recycling

Vs.

Full Depth Reclamation

Asphalt Recycling Recycle AC to:

• Stable Base

•Within 1” of less Supportive Material

Surface Course

Cold Recycled Asphalt Existing Asphalt

Existing Base

Existing Asphalt

Existing Base

Full Depth Reclamation (FDR) Improves existing materials in-place to provide greater structural support and

reduction of imported material.

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Asphalt In-place Recycling

• Partial Depth – Don’t Contaminate Product

• Cold In-Place (CIR) 2 to 5 Inches

• Bituminous Recycling Agent

• Emulsified Asphalt

• Foamed Asphalt

• Recycling Additive

• Dry Cement

• Lime Slurry

Where to Use In-Place Recycling

• Where mill and fill is considered

• CIR - All cracking distresses provided not base related

• Logistics - Should accommodate train

Pavement Conditions that Can be Addressed by Cold In-Place Recycling

Ruts < 3/4 in > 3/4 ?1 Crack Fatigue ?1 Longitudinal Transverse Block Surface Dry Flushing Bleeding Variable Raveling Potholes Texture - Rough

Ride - Poor Poor Drainage no Snow Plow Use Low Skid Resistance Asphalt Crumb Rubber no Stripping Pavement ?2 Paving Fabrics ?3

Structural Deficiency no Base Failure no Questions? 1. Provided not base, subgrade or unstable mix

related. 2. Depends on severity. May be able to add

antistrip additive. 3. No problem if properly installed. If not,

logistical issue with additional costs for disposal.

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Pavements Not to be In-place Recycled

Poor Drainage

Poor Base

Stripping

Will not fix base problems!

Paving fabric makes it tough! •Possible but messy for CIR

Fabric

Asphalt Rubber - Limitations

Quality Phase 2 Before Construction

Engineered Approach

• Sampling of In-place Materials and Conditions

• Must Do’s

• Coring For Thickness

• Dynamic Cone Penetrometer (DCP)

• Other Useful Information

• Ground Penetrating Radar

• Full and Hand - Falling Weight Deflectometers (FWD)

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D

L

D

Coring – For Depth Use In Mix Design

Core measured to the nearest 1/8-inch (3-mm) and placed in a

separate container and labeled

Cores in Lab cut to planned

recycling depth and only that

portion to be recycled used for

mix design

Centerline

Edge of Pavement

Edge of Pavement

DCP DCP Acceptable Marginal Poor

Each Set of 10 Blows < 6 Inches <150 mm

6 to 10 inches 150 mm to 250 mm

> 10 Inches > 250 mm

Inches per Blow mm per Blow

0.6 15

0.6 to 1.0 15 to 25

> 1.0 > 25

Addresses Subgrade:

To Support Train

To Support Temporary Traffic

Mix Design Mix Design Will Be Covered by Ryan Proctor in a separate presentation

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Quality Phase 3 During Construction

CIR Quality

• Environmental Conditions

• Recycled Mixture

• Geometrics

• Compaction

• Curing and Protection

• Smoothness

After

Before

Environmental Conditions

• CIR should not performed during excessively wet conditions, nor started if rain is imminent

• Minimum ambient and RAP temperature of 50°F (10°C)

• Overnight ambient temperature above 35°F (2°C)

• Sunlight best for curing with an emulsified asphalt. Compaction completed a minimum of ½ hour before sunset. Foamed asphalt tends to be less sensitive

Decreased Service Life - Adequate cohesive strength is not achieved if

curing is incomplete

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Mixture

Decreased Service Life - Non-homogeneous

mixture; incorporation of deleterious materials;

wrong application rate of recycling agent,

water or any additives

• Calibrate mixing system to ensure that the recycling agent, water and additives are added at the proper rates specified in mix design

• Beginning of each season with full material calibration

• Every lot during project by in-place volumetrics

• End of each day by volumetrics and certified delivery weight tickets

Mixture Cont.

• Pugmill/mixing chamber must provide homogeneous mixing and coating of recycling

agent, additives and water

• Pickup machine, if used, must pick up entire windrow

• Moisture content of recycled mixture

• Sample and test every ½ mile (0.8 km) or upon visual change

• Quality of recycling agents and additives

• Temperature at application

• Certificate of Compliance and Analysis with each load

• Field verification tests of each load of recycling agent

Sample Each Tanker of Recycling Agent Prior to Use

Foamed Asphalt

Half Life and Expansion Ratio

Emulsified Asphalt

Visual Sieve Test

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Mixture Cont.

• Crushing and sizing of RAP meets maximum gradation

• Sample and Test – Start of each day and every ½ mile (0.8 km) thereafter

• Crushing and sizing of RAP compared to Mix Design gradations

• Sample and Test – Twice per day for first two days and once per day thereafter or upon visual change

• Air dried gradation measured to No. 30 sieve

Geometrics

• Depth of Milling – Measure every 100 ft. (33 m)

• Cross Slope – Measure with smart level every 300 ft. (100 m)

• Depth of Recycled Material – Measure ongoing, recording every 1/8 mile (200 m)

• Mat Width – Measure ongoing, recording every 1/8 mile (200 m)

• Overlap of Minimum of 4 inches (100 mm) – Measure ongoing, recording every 1/8 mile (200 m)

• Utilities should be double adjusted to avoid stopping and starting the train and latency of adding materials during mixing

Decreased Service Life - Failure to recognize structural

inadequacies such as too thin of pavement or recycle

depth or poor cross slope

Compaction

• Establish Breakover Point/Maximum Density and Rolling Pattern

• During a control strip and if significant changes in mix properties

• Test by nuclear density for each roller pass in exact same location

• Test In-place density with nuclear gauge at random locations

• Once per ¼ mile (200 m)

• Relative compaction within 5% of maximum density

• Verify rollers have working water to prevent pickup and raveling

• Re-roll if required to reduce voids after curing

Decreased Service Life – Inadequate compaction leads to

lack of stability and cohesion. Secondary compaction from

traffic caused by insufficient rolling

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Curing and Protection

• Fog seal at the end of shift to minimize raveling during curing

• Apply sand blotter to avoid pickup of fog seal

• Allow to cure prior to surface course and re-roll (if necessary)

• A minimum of 2 days and to a moisture content of less than 3.0%

• Or after 10 days free of rain

Decreased Service Life – Insufficient curing leads to

lack of cohesion. Raveling during curing is the most

common distress of CIR

Smoothness

• Check at joints and ongoing, recording every 1/8 mile (200 m)

• < 3/8 inch (10mm) over a 10 feet (3 m) straight edge in any direction

Decreased Service Life – Due to poor ride

quality/excessive bumps

Key to Successful Recycling Good Communication and Education

• Unfamiliar with the Processes - Ask an ARRA Recycling Contractor to Review the Project and

Specifications Before the Bid. Use Their Expertise and Experience

• Preconstruction Personnel Training (PPT)

• Provides Reasonable and Similar Expectations Amongst All Parties

• Get’s Everyone on the Same Page

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In Summary Let’s Get It Right!

• Due Your Homework Before Construction to Avoid Surprises

• Good Recycling Contractors Want Stringent Quality Standards and Specifications

• More Agency Successes Lead to More Successful Contractors

Thank You

Darren Coughlin President, Coughlin Company Inc.

435-703-1268

Darren@Coughlincompany.com

Questions ?