Ray MyersExecutive Director of the

Asphalt Interlayer Association

www.info@aia-us.org916-933-9140

“Using Geosynthetics with Flexible Pavement

Systems”

THERE ARE SO MANY OPPORTUNITIES FOR

INFRASTRUCTURE IMPROVEMENTS, COST SAVINGS & INCREASED

PROFITSUSING GEOSYNTHETICS

BELOW AND IN HMA/WMA

GEOSYNTHETICS BELOW

Woven GeotextilesNonwoven GeotextileSubgrade Geogrids

IN Paving FabricsPaving MatsPaving Grids

Composite Paving GridsComposite Drainage Products

What’s new? Caltrans Section reduction with

Geosynthetics 2009 Subgrade Geotextiles 2012 Subgrade Geogrids

GRCS Geosynthetic Reinforced Chip Seal UCDavis study on light reflection with GRCS New products by Geosynthetic Manufacturers NTPEP National Transportation Product

Evaluation Program Paving Fabric Bonding Agent [details from

AIA]

Guide for Designing with Subgrade Enhancement

Geotextiles

Geotextiles[SEG’s] - 2009

Geogrids [ABEG’s] -2012

http://www.dot.ca.gov/hq/maint/Pavement/Offices/Pavement_Engineering/PDF/Subgrade_Enhancement_Geosynthetic_Design_and_Construction_Guide.pdf

Woven Geotextiles

Nonwoven Geotextiles

Geogrid for Base Reinforcement and Subgrade Stabilization

Most engineers/field personnel have used Geosynthetics (Grids and Geotextiles) to

bridge unsuitable soils when they were encountered on the

jobsite

However, now we have the tools to

proactively design for those conditions!

FHWA summary of factors that affect pavement life1. Water2. Traffic Load3. Subgrade Quality4. Maintenance5. Age6. Quality of Construction

FHWA Technology Transfer

Factors Affecting Pavement Life

1. Water creates 80% of the problems2. Traffic Load3. Subgrade Quality4. Maintenance5. Age6. Quality of Construction

FHWA Technology Transfer

When water is present in the aggregate base traffic

loading moves fines up & contaminates the aggregate

base Fines lower the load

bearing capacity of that aggregate base.

REED & GRAHAM INC.

Water Table

Ways in which Water Enters the Road

Through Permeable Surface

Capillary Flow

Seepage fromHigh GroundLateral Flow

from Roadside

To mitigate the impacts of water on a pavement

section: • Water (Side) Edge Drains• Water (Bottom) SEG’s• Water (Top) Interlayers

To mitigate the impacts of water on a pavement

section: •Water (Side) Edge Drains• Water (Bottom) SEG’s• Water (Top) INTERLAYERS

Filtration: Typically Nonwoven

REED & GRAHAM INC.

To mitigate the impact of water on a pavement

section coming from: • (Top, Side, Bottom) Edge Drains

•(Bottom) use SEG’s Subgrade Enhancement Geotextiles

• (Top) Interlayers

Separation Application

What happens Under the pavement ?

1. SeparationNow 2.

Stabilization

Stabilization Application

Biaxial Geogrid

Property Test Value

Aperture size, incha

min and max Calipered 0.8‑1.3 x 1.0‑1.6

Rib thickness, inchmin Calipered 0.04

Junction thickness, inchmin Calipered 0.150

Tensile strength, 2% strain, lb/fta

min ASTM D 6637 410 x 620

Tensile strength at ultimate, lb/fta

min ASTM D 6637 1,310 x 1,970

Ultraviolet resistance, percentmin retained tensile strength, 500 hours

ASTM D 4355 100

Junction strength, lb/fta

min ASTM D 7737 1,220 x 1,830

Overall flexural rigidity, mg-cmmin ASTM D 7748 750,000

Torsional rigidity at 20 cm-kg, mm-kg/degb

min

GRI:GG9 0.65

aMachine direction x cross directionbGeosynthetic Research Institute, Test Method GG9, Torsional Behavior of Bidirectional Geogrids When Subjected to In-Plane Rotation

Section Reduction with the use of a Geotextile and or a Geogrid produce alternate designs that can reduce Aggregate Base by as much as 30%! Cost Optimization

  A B C D E F G H I J K L M

Traffic Index 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5 9.5

% Trucks 8% 8% 8% 8% 8% 8% 8% 8% 8% 8% 8% 8% 8%

% Growth 4% 4% 4% 4% 4% 4% 4% 4% 4% 4% 4% 4% 4%

R-value 10 10 10 10 10 10 10 10 10 10 10 10 10

Drain Coeff. 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0

AC/AGG 3.2 3.2 3.2 3.2 3.2 3.2 3.2 3.2 3.2 3.2 3.2 3.2 3.2

A/C $/ton $75 $75 $75 $75 $75 $75 $75 $75 $75 $75 $75 $75 $75

BASE $/ton $40 $40 $40 $40 $40 $40 $40 $40 $40 $40 $40 $40 $40

SEG/$SY $1.50 $1.50 $1.50 $1.50 $1.50 $1.50 $1.50 $1.50 $1.50 $1.50 $1.50 $1.50 $1.50

 

Required # 5.71 5.71 5.71 5.71 5.71 5.71 5.71 5.71 5.71 5.71 5.71 5.71 5.71

Design # 5.71 5.71   5.73 5.73   5.74 5.74   5.77 5.77   5.73

ASPHALT (") 6.0 6.0 6.0 6.5 6.5 6.5 7.0 7.0 7.0 8.0 8.0 8.0 9.0

BASE (") 21.5 17.0 21.0 20.0 15.5 20.0 18.5 13.5 18.5 15.5 10.5 15.5 7.0

Sect.total 27.5 23.0 27.0 26.5 22.0 26.5 25.5 20.5 25.5 23.5 18.5 23.5 16.0SEG Y/N N HSW HSW N HSW HSW N HSW HSW N HSW HSW HSW

Cost/LnM$ $1.14M $1,006   $1,121 $979   $1,092 $932   $1,037 $878   $799

Excav $k's $1.3M $1,122 $1,314 $1,254 $1,090 $1,281 $1,222 $1,037 $1,249 $1,157 $972$1,18

4 $880k

Design Life 20 20 35 20 20 35 20 20 35 20 20 35 20

Cost Savings %   12.7% -2.1% 2.5% 15.2% 0.3% 5.0% 19.3% 2.9% 10.0% 24.4% 7.9% 31.6%

Save k$/ln mile   $164 ($28) $32 $196 $5 $64 $249 $37 $129 $314 $102 $400k

CALTRANS HWY 53

CLEARLAKE, CA

01-3986A4 ~$150,000 to the

contractor

We’ve coveredGeosynthetics BELOW the pavement

Now Geosynthetics IN the pavement

Caltrans MTAGhttp://www.dot.ca.gov/hq/maint/

MTA_GuideVolume1Flexible.html

Types of InterlayersMaterial SpecificationsDesign Criteria Application Rates

DETERMINETYPE AND LEVEL OF

DISTRESS!!!!

Unacceptable pavement conditions to utilize interlayers

Rutting Internal Rutting due to unsatisfactory base Loose Asphalt Inadequate structure Standing water Excess traffic Quality of milling Lack of preparation

Unsuitable pavements

Rutting or shoving AC

Unacceptable Grinding for most interlayers

Finish/Profile Grinding

Factors Affecting Pavement Life

1. Water creates 80% of the problems2. Traffic Load3. Subgrade Quality4. Maintenance5. Age6. Quality of Construction

FHWA Technology Transfer

Why Use Interlayers?To provide an extension of pavement life by doing one or more of the following:

1.Reduce the pavement permeability by creating a moisture barrier

2.Reduce reflective cracking3.Provide stress relief4.Reinforcement

When to use Interlayers?

new construction,

rehabilitation or preservation in conjunction with an overlay or surface treatment

Types of Interlayers

Fabric - Polypropylene Mat - Polyester/Fiberglass Grids

Non Composite Composite

Peel & Stick Membranes

Paving Fabric

Paving Fabric: A non-woven geotextile fabric that is saturated with asphalt cement and placed with an overlay or chip seal.

Warm Mix with Paving Fabric

GRCS Geosynthetic Reinforced Chip Seals

Go to www.aia-us.org

This process is used world wide

Successful GRCS Projects that have been in place for 25 years and yet to require additional treatment.

The specifications differ from that of fabric under an overlay

GRCS: Terminal Blend Rubber Chip Seal over

Paving Fabric

Paving Mat

Pavement Reinforcing Grid

Very high strength 50kN = 11240 pounds force 100kN = 22480 pounds force 200kN = 44960 pounds force

That is why the term reinforcing is appropriate

Mill & Fill Failure

Pavement Reinforcing Composite Grid

Paving Grids (Non Composite)

MULTI-AXIAL COMPOSITE PAVING GRID

Recycling Paving Fabric

Can Asphalt with Paving fabric be Recycled?

ABSOLUTELY!!!!!“Syracuse Revisited”

Aia-us.orgConsider Pavement

Fabric Bonding Agent

To Recycle the system must be installed correctly

How much binder has been placed?

Post weigh test unit

Non Composite Paving Grid

Composite grids must be shingled on curves

Composite Membranes

Developed in 2010/2011 in part through then leadership of an AIA member

Allows states to get away from traditional APL/QPL’s

Enables inspectors to be certain which product is being used

NTPEPNational Transportation Product Evaluation Program

·Product name·Manufacturer·Location manufactured·AASHTO/NTPEP reference if applicable

THINK INSIDE THE GREEN BOX WITH HMA, WMA & GRCS TO BUILD PAVEMENTS THAT:A. LESS EXPENSIVEB. LAST LONGER C. USE LESS NATURAL RESOURCES D. GENERATE MORE PROFIT

SO MANY BENEFITS OF THE ALLIANCE OF ASPHALT & GEOSYNTHETICS WHETHER BELOW OR IN THE PAVEMENT SECTION

Ray MyersExecutive Director of the

Asphalt Interlayer Association www.info@aia-us.org

916-933-9140

“Using Geosynthetics with Flexible Pavement Systems”