SECTION 02979
ASPHALT INTERLAYER REINFORCEMENT SYSTEM
PART 1 GENERAL
1.1
SECTION INCLUDES
A.
1.2
RELATED SECTIONS
A.
1.3
1.4
Asphalt interlayer reinforcement system.
Section 32 12 16 – Asphalt Paving.
REFERENCES

Asphalt Institute Handbook.

AASHTO Standard Specification for Highway Bridges.

ASTM D276 – Standard Test Methods for Identification of Fibers in Textiles.

ASTM D4595 – Test Method for Tensile Properties of Geotextiles by the Wide-Width
Strip Method.

ASTM D4694 – Standard Test Method for Deflections with a Falling-Weight-Type Impulse
Load Device.

ASTM D4759 – Standard Practice for Determining the Specification Conformance of
Geosynthetics.

ASTM D5340 – Standard Test Method for Airport Pavement Condition Index Surveys.

ASTM D5261 – Standard Test Method for Measuring Mass per Unit Area of Geotextiles.

ASTM D6637 – Standard Test Method for Determining Tensile Properties of Geogrids by the
Single or Multi-Rib Test Method; 2001.

DIN EN ISO 10319 (2008-10) – Geosynthetics - Wide-Width Tensile Test (ISO 10319:2008).

FHWA Federal Highway Administration – Design Guidelines.
SYSTEM DESCRIPTION
A.
Flexible Pavements: Provide GlasGrid interlayer reinforcement system installed between
asphalt layers in a pavement structure to distribute loads, reinforce the pavement and
reduce reflective cracking distresses.
B.
Rigid or Composite Pavements: Provide GlasGrid interlayer reinforcement system installed
between freshly leveled asphalt overlay to absorb the strain and stress energy developed by
traffic-induced working concrete joints and by slab shrinkage and expansion due to thermal
changes.
02979-1
1.5
SUBMITTALS
A.
Submit under provisions of Section 01 30 00.
B.
Submittals of “Shop and Setting Drawings”, “Working Drawings”, “Catalogue Data” and
“Certifications” for review shall be submitted in accordance with appropriate sections of the
General Provisions. Submittals and Certifications required are as follows:
C.
1.
Catalog data and recent certification, performed at most 1 year prior to the submittal,
showing that the asphalt reinforcement grid and tack coat meets the specified
requirements.
2.
No sample of the tack coat is required.
3.
Manufacturer’s installation instructions and general recommendations.
Product Data: Manufacturer’s data sheets on each product to be used, including:
1.
Preparation instructions and recommendations.
2.
Storage and handling requirements and recommendations.
D.
Samples: Enough material should be supplied to prepare two samples of each type of
fiberglass grid and interlayer grid specified. Each sample shall be 305 mm by 203 mm (12”
by 8”) and include a minimum of 5 ribs.
E.
Certification: Indicate minimum average roll values, or provide annual letter of compliance
from accredited third party testing facility, and tests used to determine those properties.
Provide documentation to show that testing has been performed and that the performance
requirements have been met.
F.
List of at least five comparable projects that are similar in terms of size and application, and
where the results of using the specific asphalt reinforcement grid and tack combination can
be verified after a minimum of three years of service life.
G.
Additional information as requested by the Engineer to fully evaluate the product.
02979-2
1.6
QUALITY ASSURANCE
A.
B.
C.
1.7
1.8
Manufacturer Qualifications:
1.
Manufacturer with at least 10 years of documented experience in the manufacture and
installation of fiberglass interlayer grids to reduce thermal or load associated cracking
distress, and in the manufacture of the tack coat that meets the specification.
2.
Manufacturer with documented evidence of an established quality control program to
assure products with consistent compliance with the requirements of this specification.
Such a program would be ISO 9001:2008 Registration.
3.
Annual conformance testing performed by an accredited third party testing facility.
Installer Qualifications:
1.
Firm with documented experience in the installation of fiberglass interlayer grid
systems with at least two projects of similar construction and scope.
2.
Include brief description of each project by name, and phone number of owner’s
representative knowledgeable in each listed project.
Pre-Construction Meeting:
1.
Prior to construction of interlayer reinforcement system, conduct a meeting at the site
with the materials supplier, the installer, and the Contractor to review the preparation
and installation requirements.
2.
Notify the Owner and the Engineer at least 3 days in advance of the time of the
meeting.
DELIVERY, STORAGE, AND HANDLING
A.
Store products in manufacturer’s unopened packaging until ready for installation.
B.
Store in a dry, covered location that is free of dust, dirt, and moisture. Prevent excessive
mud, fluid concrete, asphalt, or other deleterious materials from coming in contact with
reinforcement grid materials.
C.
Store at temperatures between minus 29°C (minus 20°F), below 82°C (180°F) and
maximum relative humidity of 85%.
PROJECT CONDITIONS
A.
Do not place grid reinforcement when the asphalt surface is wet, or contaminated with oil,
soil or excessive dust.
B.
Existing pavement should show no signs of poor drainage, pumping of fines, excessive
deflections or structural instability.
C.
Receiving surface shall be smooth, with the existing cracks pretreated per SHRP-H-348.
02979-3
D.
Make all repairs as required prior to placement of interlayer system.
E.
Do not install asphalt on the grid reinforcement when the underlying asphalt surface is hotter
than 60°C (140°F) or in the case of new asphalt, do not install prior to the asphalt cooling to
43°C (110°F) at least once previously.
PART 2 PRODUCTS
A.
Acceptable Manufacturer: Saint-Gobain ADFORS, 1795 Baseline Rd., Grand Island, NY
14072-2010 USA, Phone: 800-866-9445 or 716-775-3900, and their authorized distributors.
B.
Substitutions submitted no later than 16 days prior to bid will be considered in accordance
with provisions of Section 01 60 00.
MATERIALS
A.
Material shall be certified manufactured in the USA
B.
The asphalt reinforcement grid shall consist of a high strength, fiberglass grid custom knitted
and coated with an elastomeric polymer and self-adhesive glue.
C.
In addition, the reinforcement grid shall have the following/adhere to the following Minimum
Average Roll Values (MARV) for material properties and should adhere to the strength
properties in Table 1.
Table 1 –Material and Strength Properties
PRODUCT
PROPERTIES
Material Properties
2.2
MANUFACTURERS
METHOD
Aperture Size
(Center to Center)
Percent Open Area
UNITS
mm (inch)
CW-02215
MOD.1
%
Fiberglass Coating
Mass / Unit Area
ASTM D5261
Roll Width
Strength
Properties
2.1
Fiberglass Coating
Softening Point
g/m²
(oz/yd²)
m
(ft.)
Type 1
Type 2
12.5 x 12.5
(0.5 x 0.5)
25.0 x 25.0
(1.0 x 1.0)
Greater than
or equal to 50
Elastomeric
Polymer
405
(12.0)
1.5
(5.0)
Greater than
149
(300)
Greater than
or equal to 50
Elastomeric
Polymer
405
(12.0)
1.5
(5.0)
Greater than
149
(300)
ASTM D36
°C
(°F)
Tensile Strength
(MD x CD)
ASTM D6637
kN/m
(lb./in)
100 x 100
(560 x 560)
100 x 100
(560 x 560)
Tensile Strength
@2%
ASTM D6637
kN/m
(lb./in)
80 x 80
(456 x 456)
80 x 80
(456 x 456)
02979-4
Elongation at Break
1
ASTM D6637
(%)
Less than
3
Less than
3
- Army Corp of Engineers test method correlated to light emitted through fabric.
Table 2 Product Performance Requirements
Performance Requirements
TEST DESCRIPTION
TEST METHOD
METHOD OF
MEASURE
Coating Softening
Temperature vs. HMA
Asphalt Binder
Compaction
Temperature
Temperature Comparison
Job Mix Formula
Compaction
Temperature
Requirement
Field Millability and
Recyclability Validation
Field Milling of Asphalt with
GlasGrid
References or Reports
Asphalt : Grid composite
stiffness for durability of
composite layers over
life of pavement during
individual and long term
deformation
3Pt Beam Test at 70°F, Grid
with polymer tack at mid
depth relative to a control
with polymer emulsion tack
coat – cyclic stress
controlled loading
Minimum
Improvement
Factor vs. Control
Fatigue and Rutting
Performance
Fatigue and Reflective
Cracking
Full Scale Crack and
Durability Test
1
:
Circular Full Scale APT
Testing vs. Control
MMLS3 Scaled APT 1
Testing vs. Control
NCAT Test Track
Performance
1
1
Rutting and Fatigue
PERFORMANCE
Coating
Softening Point >
HMA Compaction
Temperature
Documented
Experience
> 3x
> 2x (rutting)
>3x (fatigue)
Fatigue and Reflective
Cracking Testing
Number of ESALS
>3x
>40 million
APT – Accelerated Pavement Testing
Note to specifier – Delete Text box prior to placement in the project specification

Grid aperture size selection:
Type 1 Grid, is to be used for asphalt mixes with a maximum particle size, less than 12.5 mm (1/2”)
For coarser mixes equal to or greater than 12.5 mm (1/2”) use Grid Type 2.
The grid size may also be selected based on local environmental conditions, mix stability,
past performance or user preference.
02979-5
PART 3
3.1
3.2
EXECUTION
PREPARATION
A.
Do not begin GlasGrid interlayer system until existing pavement condition has been
evaluated and all repairs have been completed.
B.
Seal cracks between 3mm (1/8”) and 6 mm (1/4”) with an acceptable crack filler. Repair
wider cracks using a method that provides a level surface. All holes shall be filled with hot
asphalt and compacted level with adjacent surfaces.
C.
Surfaces shall be mechanically cleaned by sweeping and vacuuming and be free of oil,
vegetation, sand, dirt, water, gravel, and other contaminants prior to placement of interlayer
reinforcing.
D.
If subgrade preparation is the responsibility of others, notify Engineer of unsatisfactory
preparation. Do not begin work until unsatisfactory conditions have been rectified.
E.
Cracks shall be marked and recorded prior to and after the true and leveling course.
Identifying and preserving the crack location will ensure that the grid is properly centered on
each crack when full grid coverage of the site is not specified.
INSTALLATION
A.
Storage of Material:
1.
Prior to use, store reinforcement grid rolls in unopened packaging vertically (on end)
under dry, covered conditions free from dust, dirt, and moisture to prevent roll
distortion and contamination.
2.
Store the product at temperatures above minus 29°C (-20°F), below 82°C (180°F)
with a relative humidity of less than 85%.
B.
Install GlasGrid interlayer reinforcement system in accordance with Tensar International’s
installation guidelines.
C.
Leveling Course:
D.
1.
Leveling course shall be a minimum thickness of 19 mm (3/4”) and shall have a
surface temperature cooler than 60°C (140°F) and will have cooled to 43°C (110°F) at
least once previously.
2.
Crack areas showing excessive surface irregularities shall be leveled prior to
placement.
3.
Slab joint showing upward tenting shall be saw-cut to relieve pressure prior to
leveling.
Asphalt Reinforcement Grid Placement:
1.
Surface temperature shall be between 5°C and 60°C (40-140°F) prior to laying the
grid reinforcement.
02979-6
3.3
2.
The placement surface must be dry. Since moisture affects the adhesion of the grid to
the pavement surface, grid placement should not be undertaken if rain is likely to fall
prior to covering the grid with an asphalt mat overlay. Grid that is placed and will not
adhere due to moisture shall be removed and replaced at the Contractor’s expense.
3.
Reinforcement grid shall be laid out by mechanical means or by hand using sufficient
pressure to eliminate ripples. Remove any ripples by pulling the grid tight. Cutting of
the grid may be done on tight radii to prevent ripples.
4.
Lap transverse joints in the direction of the paving 76 mm to 152 mm (3-6”);
longitudinal joints shall be overlapped 25 mm to 50 mm (1-2”) or as recommended by
the manufacturer, whichever is greater.
5.
Following the placement of the material, activate self-adhesive glue by rolling with a
rubber coated drum roller or a pneumatic tire roller. In no instance shall steel-wheeled
or vibratory rollers be used. Rolling shall continue until the adhesive is activated and
the grid is bonded to the truing and leveling course. Generally, this can be
accomplished in one or two roller passes. If bond is not readily achieved then
identification of the cause is required. This cause is typically due contamination on the
smooth surface, in the form of either water or debris During rolling operations, roller
tires shall be kept clean to the satisfaction of the Engineer. Reinforcement shall be
laid and rolled over ironworks (i.e., manhole covers, drainage grates, etc.). Once the
grid has been rolled, these portions of the mats covering the ironworks shall be
removed by cutting the reinforcement grid with a utility knife or other similar tool.
6.
Construction and emergency vehicles will be allowed to run on the reinforcement grid
after rolling. However, any damaged or de-bonded sections of the grid resulting from
these vehicles, as determined by the Engineer, shall be immediately replaced with
new grid sections, taking care to place the adhesive backing down and to overlap the
grid already in place. As before, replacement sections shall be rolled in accordance
with manufacturer’s recommendations. Grid shall be rolled until the adhesive is
activated and the replacement grid section is bonded to the truing and leveling course.
Any dirt, dust or other contaminants deposited on the grid-covered truing and leveling
course by the construction equipment, maintenance vehicles, or emergency vehicles
shall be removed by mechanical sweeping or vacuuming the surface. No additional
payment will be made to replace sections of grids damaged by construction
equipment, maintenance vehicles, or emergency traffic. No payment will be made to
sweep or vacuum the surface, or to remove contaminates deposited by such traffic.
7.
Protect the asphalt reinforcing grid until placement of the finished asphalt topping.
Repair damaged sections prior to placement of finished asphalt topping.
8.
Place the asphaltic overlay course the same day the interlayer reinforcing grid is
placed.
9.
Overlay course shall be a minimum thickness of 40 mm (1-1/2”).
10.
When a tack coat is specified, the approved tack coat should be used in conjunction
with the geogrid interlayer system.
a.
If placed prior to the interlayer it must fully cure prior to placement of interlayer,
b.
if placed after to interlayer material it must fully cure prior to any construction
traffic over the surface including paving
FIELD QUALITY CONTROL
02979-7
A.
Testing and Inspection will be provided by the Owners Testing Agency as specified in
Section 01 40 00 Testing and Inspection Services. Notify the Engineer 72 hours in advance
of testing.
B.
Testing and Inspection shall be provided by an independent laboratory provided by the
Contractor and acceptable to the Engineer.
C.
Perform adhesion tests in accordance with the following:
D.
1.
Place approximately 1 m² (1 sq. yd.) of interlayer reinforcing grid on a properly
prepared leveling course that is representative of the project condition.
2.
Activate self-adhesive glue by rolling with a rubber-tired roller or by applying adequate
pressure to fully activate the pressure-sensitive adhesive.
3.
Use a calibrated spring balance by inserting the hook of the balance under the center
of the grid and pulling upward until the grid starts to pull away from the surface.
4.
A 9 kg (20 pound) pull is required without pulling the grid free or creating ripples in the
grid.
5.
Consult grid manufacturer if grid does not meet this pull rating and do not place
asphalt topping until an acceptable adhesion is achieved.
Frequency of Tests:
1.
3.4
Adhesion Test: Provide a minimum of one test per 300 m² (3,000 sq. ft.) of surface
area.
MANUFACTURER’S FIELD SERVICES
It is suggested that a manufacturer’s representative be present on site for the initial start of the
installation of the interlayer reinforcing grid. The contractor shall provide sufficient advanced
notification.
3.5
PROTECTION
A.
Protect installed product until completion of project.
B.
Repair or replace damaged products before Substantial Completion.
END OF SECTION
02979-8