Pavement Preservation

CALIFORNIA ASPHALT PAVEMENT ASSOCIATIONFALL ASPHALT PAVEMENT

CONFERENCESACRAMENTO, CA

October 29 – 30, 2014

Hans Ho, PhDTechnical Director

(Retired)

Sum of all activities to provide and maintain serviceable roadways

Includes

Corrective & Preventive Maintenance

Minor rehabilitation

Does not include

Reactive maintenance

Major rehabilitation or reconstruction

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Cost effectiveness Energy savings Reduced emissions Reduced user costs Life extension User satisfaction Safety

10/31/2014 3

Right Treatment

Right Pavement

Right Time

“

How do I get the decision makers to understand that “worst first” does not work?

Pavement Preservation - Concept

Time or Traffic

Condition(or $ needed) Rehabilitation

Trigger

Preventive Trigger

Original Pavement

Optimal Timing

$1

$30-$40

ASSUMPTION: You own 300 lane miles of road & Have a budget of $1.5M for:

• pavement reconstruction• rehab • maintenance

• Typical Breakdown

• $1M for reconstruction and rehab =“worst first” scenario &

• $500K for maintenance

Reconstruction ~ $25.00 per yd2

• (6”mill and fill with HMA @ $75/ton)

• $1M÷$25/yd2 = 40K yd2 or 5.7 LM

Cost of maintenance ~ $4 per yd2

• $500K÷$4/yd2 = 125K yd2 or 17.8 LM

Total LN Mi repaired is 23.5

For 300 lane miles, road cycle will be ~13 years

Costs of reconstruction ~ $25.00 per yd2

$500K÷$25/yd2 = 20K yd2 = 2.8 LN Mi

Cost of maintenance ~ $4.00 per yd2

$1M÷$4/yd2 = 250K yd2 = 35.5 LN Mi

Total LN Mi repaired ~ 38 For 300 lane miles, road cycle will be ~ 8 years

• Management Support• Public understanding and

acceptance• Dedicated & Continuous

Funding• Good products and

workmanship• Contractor relationship• In house training

Fog & Rejuvenating Seals ~$0.50 - $0.75/yd2

GME – Gilsonite Modified Emulsion ~$0.95/yd2

Chip Seals Cold Applied-▪ PMCRS-2h ~$1.75/yd2

▪ PMRE ~$2.00/yd2

Hot Applied –▪ Asphalt Rubber ~$2.75 - $3 /yd2

▪ Terminal Blends ~$2.50 - $2.75/yd2

Slurry Seals ~$1.50/yd2

Micro-Surfacing ~$1.75/yd2

Bonded Wearing Course ~$9- $10/yd2

Benefits:

• Renews aged asphalt pavements

• Seal small voids and surface cracks

• Improve lane delineation and pavement marking

• Prevent raveling of loose aggregate with chip seals

• Prevents water penetration

Material:

• SS-1h

• CSS-1h

• CQS-1h

• PMRE

• Gilsonite Modified Emulsion

Material need to be diluted

Light application of diluted slow-setting asphalt emulsion

Common uses Seal aged surface

Improve lane delineation Typical treatment life: 1 to 3 years

Heavily aged, dense-graded HMA

Open-graded HMA

Fog seal over existing chip seal

1. Asphalt – PG graded asphalt 2. Rejuvenator - Acts to penetrate and add

additional maltenes to the asphalt matrix to restore flexibility to the binder. Good aggregates don't wear out as fast as asphalt becomes brittle

3. Gilsonite – Mined asphalt. Acts as a modifier to increase the polar content to form a film thickness that no other product can match.

Reduces raveling, by locking in fines in mat. Blacker surface for better line delineation allows us to use blast furnace slag to help

restore the loss of minor fines and improve the skid numbers.

Department of Defense only uses GilsoniteModified Emulsion to reduce (FOD) Foreign Object Debris (Proprietary product known as GSB-88)

Application rate: 0.45 to 0.70 l/m2 (0.10 to 0.15 gal/yd2)

Spray temperature range: 20 to 70 °C (70 to 160 °F)

Spray Bar and Nozzles

Single Overlap hh

Roadway SurfaceDouble Overlap

Roadway SurfaceTriple Overlap

Roadway Surface

h

BAD…

Equipment inspection

Good

Using excess emulsion for the existing pavement surface

Placing in wet and/or cool weather

Over or under dilution Incompatible water for

dilution Skid issues

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Chip Seals Chip seals consist of asphalt emulsions, asphalt rubber

binder or terminal blend binder followed by a single layer

of aggregate.

Chip seals can consist of multiple layers (single and

double chip seals), and are typically followed with a fog

seal. Chip seals can also be covered with a slurry or

microsurfacing thereby creating a “cape seal”.

Typical Treatment life: 5 – 7 years

Chip Seals

Benefits:

• Renews aged asphalt pavements

• Improves surface friction course

(skid resistance)

• Seals small voids and surface cracks

• Improves lane delineation and pavement marking

• Prevents raveling of loose

aggregate with chip seals

• Prevents water penetration

Polymer Modified Emulsion Chip Seal PMCRS-2h Scrub Seals PMRE (Rejuvenating Chip Seals) Usually .25-.40 gal/yd2 binder

Hot Applied Chip Seal Asphalt Rubber Chip Seal Terminal Blend (Modified Binder Chip Seal) Usually .35-.6 gal/yd2 binder

Chip over Paving Fabric .25-.35 gal/yd2 binder plus chip seal over top

Step 4 Construction Inspection

Roll

Chip

Spray

Sweep

Sweep Again

Start/Stop Application on Building Paper Chipper Within 100’ of Distributer Chipper Speed =NO rolling Chips Application Appears Uniform Rollers Tight to Chipper, Speed 7mph

maxChipper always within 100 feet of Distributer

NOTE DISTANCE

Poor Workmanship

Inadequate/Uneven Aggregate Coverage or Precoating Issues

Polymer Modified Rejuvenating Emulsion Broom scrubs material in Emulsion + Broom = the ability to eliminate

crack filling = cost savings.

• PMRE asphalt emulsion

• Sand or aggregate

• Broom is dragged behind the distributor

truck to embed the emulsion into the cracks

• On sand seals, pneumatic tired rollers

embed the sand into the emulsion

Scrub Seals using sand or aggregate:

SCRUB AND SAND SEALS

SCRUB SEALS

Emulsion Wave

Asphalt Rubber Terminal Blends

Chip over Paving Fabric

• Low volume roads

• Good seal due to high asphalt content

•.28-.35 gal/yd2 of asphalt followed by chip seal with .3-.5 gal/yd2

of emulsion or hot applied binder

• Flexible solution for a flexible road!

RAC/Sami 10 Years old “Ventura” warranty project

10 year old “Ventura” ARCS

Nothing done

Fabric ready for chip

Cape Seal

Terminal Blend Chip Seal

Improper surface preparation

Applying in cool and/or wet weather

Using dirty rock Not accounting for new

patches or flushed surfaces

Not taking traffic into account

Over spreading or under spreading binder or aggregate

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Slurry SealingBenefits:

• Improved surface friction course (skid resistance)

• Seals small voids and surface cracks

• Improves lane delineation and pavement marking

• Prevents water penetration

•Typical Treatment Life: 5 – 7 years

• Can be part of a “cape seal”

(slurry seal over a chip seal)

Existing road surface

- Laid at one-stone thickness- Largest stone bears traffic load

1/4 - 3/8”

Micro-Surfacing

Benefits:

• Chemically driven emulsion which can reduce traffic delays to

less than 1 hour

• Improved surface friction course (skid resistance)

• Seals small voids and surface cracks

• Improves lane delineation and pavement marking

• Day or night construction

• Rut filling and re-profiling

• Prevents water penetration

•Typical Treatment life: 8 – 12 years

•Can be part of a “cape seal”

(slurry seal over a chip seal)

Existing road surface

- Applied in multi-stone thickness

- Stone interlock and modified binder bears traffic load

- May be applied in multiple layers

3/8” +

3/8” +

BAD

GOOD

GOOD

Improper surface preparation or placing on badly cracked pavements

Not following the mix design Construction in wet weather Equipment not calibrated Poor workmanship, including too much water

in the mix Insufficient applications rate Inadequate QC and acceptance testing

50

Part Chip Seal Application of .13-.25 gal/SY of a polymer

modified emulsion for adhesion Part HMA Overlay

Use of gap or open graded, polymer or rubberized HMA to finish the process

Typical Treatment Life: 8 – 12 years

What is Bonded Wearing Course

From the chip seal

Spray application that seals the existing roadway

Bonding of the new surface to the old surface

Quick process – up to 50,000 SY per day

From the HMA overlay

Improved ride quality

Quick return to traffic

No sweeping or fog seal needed

Bonded Wearing Course

HMA

Emulsion

Joint Matching Device

Existing Pavement

The emulsion membrane “wicks up”around the HMA aggregates

9-12 mmcoating on aggregates

5/8”minimumDepth of Mix

3/16”Emulsionmembranedepth

The emulsion cures, bonding the mix & pavement

3/8”Nominal Ag Size

Tack Coat Application Rate:

0.14 – 0.25 gal/yd2

Lift Thickness:

¾” – 1”

Compaction:

Method – 2 passes with a minimum of two rollers in static mode

Machine is designed to reduce thermal and mechanical segregation

NY-191326.351/010103YvashHR1

Since 1998 in California

First project – Lark Ellen Blvd, Los Angeles County

Since 2002 for Caltrans

Hwy 50 over Echo Summit, Lake Tahoe

MTC Demo Project- Before

Madison from 7th

to 8th Streets

City of Oakland

Bonded Wearing Course –Applied 2003

Bonded Wearing Course – As of

March 26, 2013

California Chip Seal Association www.chipseal.org

Pavement Preservation Workshop, February, 2015 hosted by the California Chip Seal Association

www.telfercompanies.com

Thank you

Hans Ho, PhDTechnical Director (Retired)hansho@telfercompanies.com(925) 228-1515 X1329