SECTION 02979
ASPHALT INTERLAYER REINFORCEMENT SYSTEM
PART 1 GENERAL
1.1 SECTION INCLUDES
A.
Asphalt interlayer reinforcement system.
1.2 RELATED SECTIONS
A.
Section 32 12 16 – Asphalt Paving.
1.3 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.
1.4 SYSTEM DESCRIPTION
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A.
Flexible Pavements: Provide GlasGrid interlayer reinforcement system installed between
asphalt layers in a pavement structure to distribute the load and 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
1.5 DESIGN REQUIREMENTS
A.
Design GlasGrid interlayer system in accordance with the local codes and regulations and
the design guidelines of Saint-Gobain ADFORS and the following:
1.
Existing pavement should show no signs of poor drainage, pumping of fines,
excessive deflections or structural instability.
2.
Perform a field evaluation including a visual distress survey in accordance with a
pavement condition index methodology, similar to ASTM D5340, and deflection
testing such as falling weight deflectometer, similar to ASTM D4694, to determine the
effective modulus of the existing pavement section.
3.
Make all repairs as required prior to placement of interlayer system.
1.6 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.
D.
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.
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.
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E.
Certification: Shall provide minimum average roll values, provide annual letter of compliance
from accredited third party testing facility, and tests used to determine those properties.
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.
1.7 QUALITY ASSURANCE
A.
B.
C.
Manufacturer Qualifications:
1.
Manufacturer with at least 20 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.
1.8 DELIVERY, STORAGE, AND HANDLING
1
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 above minus 29°C (minus 20°F) and 75°C (167°F) and maximum
relative humidity of 85%.
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1.9 PROJECT CONDITIONS
A.
Do not place grid reinforcement when the asphalt surface is wet, or contaminated with oil,
soil or excessive dust.
B.
Do not place asphalt during wet or freezing weather that prevents conformance with
specified requirements.
C.
Do not install asphalt on the grid reinforcement when the underlying asphalt surface is cooler
than 10°C (50°F), warmer than 60°C (140°F), or in the case of new asphalt, prior to the
asphalt cooling to 43°C (110°F) at least once previously.
PART 2
PRODUCTS
2.1 MANUFACTURERS
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.
2.2 MATERIALS
A.
The asphalt reinforcement grid shall consist of a high strength, fiberglass grid custom knitted
and coated with a patent-pending elastomeric polymer and self-adhesive glue. The grid is
combined with a patent-pending multilayer tack film designed to enhance the bond between
layers of hot mix asphalt and replace conventional tack coats.
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 and the performance requirements of Table 2.
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Table 1 Material and Strength Properties
PRODUCT
PROPERTIES
METHOD
Strength Properties
Material Properties
Aperture Size
(Center to Center)
Type 1
Type 2
12.5 x 12.5
(0.5 x 0.5)
25 x 25
(1.0 x 1.0)
Greater than
or equal to 50
Elastomeric
Polymer
Greater than
or equal to 50
Elastomeric
Polymer
%
>25
>25
g/m²
(oz/yd²)
432
(12.7)
432
(12.7)
m
(ft.)
1.5
(5.0)
1.5
(5.0)
ASTM D36
°C
(°F)
Greater than
149
(300)
Greater than
149
(300)
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)
Percent Open Area
mm
(inch)
CW-02215
MOD.1
%
Fiberglass Coating
Tack Coat
% Polymer Modified
Mass / Unit Area
ASTM D5261
Roll Width
Fiberglas Coating
Softening Point
Elongation at
Less than
ASTM D6637
(%)
Break
3
1
- Army Corp of Engineers test method correlated to light emitted through fabric.
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UNITS
Less than
3
Table 2 Product Performance Requirements
Performance Requirements
TEST DESCRIPTION
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
Haversquare
loading
Minimum
Improvement
Factor vs. Control
Full Scale Plate Load
Testing
:
Fatigue and
Reflective Cracking
Testing
Plate Load Testing
vs. Control
Pavement
Composite
Modulus
APT – Accelerated Pavement Testing
PERFORMANCE
Coating Softening
Point > HMA
Compaction
Temperature
Documented
Experience
≥ 5x
MMLS3 Scaled APT
1
Testing vs. Control
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METHOD OF
MEASURE
Coating Softening
Temperature vs. HMA
Asphalt Binder
Compaction
Temperature
Fatigue and Reflective
Cracking
1
TEST METHOD
≥ 3x
≥ 1.5x
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”)
Type 2 Grid, is to be used for asphalt mixes with a maximum particle size, equal to or greater than
12.5 mm (1/2”)
The grid size may also be selected based on local environmental conditions, mix stability,
past performance or user preference.
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PART 3
EXECUTION
3.1 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.
3.2 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) 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 warmer than 10°C (50°F), 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:
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E.
1.
Surface temperature shall be between10°C (50°F) and 60°C (140°F) prior to placing
the grid reinforcement.
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.
After placement, activate self-adhesive glue by rolling with a rubber coated drum roller
or a pneumatic tire roller until proper adherence occurs. In no instance shall steelwheeled 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. 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.
Asphalt Placement
1.
Place the asphalt overlay course in accordance with Section 32 12 00. Place the
asphaltic overlay course the same day the interlayer reinforcing grid is placed.
a.
Overlay course shall be a minimum compacted thickness of 40 mm (1-1/2”)
b.
In order to activate the tack film,
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1)
2.
F.
The surface temperature must be 21°C (70°F) and the asphalt mix being
placed over the interlayer material must be placed at a minimum
temperature of 140°C (285°F).
When a tack coat is specified, the approved tack coat should be used beneath the
geogrid interlayer system.
TACK COAT APPLICATION (if required due to heavily oxidized leveling course)
1.
Application of tack may be carried out prior to the placement of the interlayer at the
discretion of the Engineer and the Contractor. Logistics site conditions and / or
environmental parameters may influence the decision. Discussions with the
manufacturer may provide additional insight into this decision.
2.
The asphalt reinforcing grid has a self-adhesive backing, so the tack coat is not
required for the installation. However, if a tack is specified for other reasons, such as
the surface is oxidized, the tack must (in the case of an emulsion tack) be allowed to
break and cure before the GlasGrid TF is placed. Breaking is defined as the point at
which the brown-colored tack turns black. Curing occurs when the residual asphalt
cement contains no solvents (water or any volatiles). After the GlasGrid TF has been
installed on the broken and cured tack coat, the adhesion test should be done prior to
placing any asphalt and prior to asphalt trucks running on the GlasGrid TF on tacked
surface.
Note to specifier:
When tack coats are specified, the following products are recommended by the manufacturer:
Type 1 – NTSS -1HM, anionic trackless tack.
Type 2 – Cationic, rapid set, CRS-2P.
Type 3 – Paving Grade AC, PG64–XX. Hot spray AC tacks work well in cooler weather, when surface
temperatures are at or below 15°C (60°F). When surface temperatures exceed 20°C (68°F), the
manufacturer recommends either raising the grade of the PG Tack coa,t or that an emulsion be
applied in place of the hot spray AC.
A.
Do not dilute emulsified asphalts at the terminal or in the field.
B.
Provide a certificate of compliance with the product specifications immediately prior to
use.
C.
Prepare surfaces as specified prior to application.
D.
Unless otherwise recommended by the manufacturer, apply tack coat at the residual rate
of 0.02 to 0.05 gallons per square yard of surface area. The rate should be specified by
the Engineer, but could vary depending on the installation or surface conditions.
E.
Protect adjacent surfaces and prevent spattering of tack coat when placed adjacent to
curbs, gutter, structures, and other adjacent surfaces. Clean any surfaces where they
have been contaminated by the tack coat.
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3.3 FIELD QUALITY CONTROL
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 a 1 m² (1 sq. yd.) of interlayer reinforcing grid on a properly prepared leveling
course.
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.
Adhesion Test: Provide a minimum of one test per 300 m² (3,000 sq. ft.) of surface
area.
3.4 MANUFACTURER’S FIELD SERVICES
A.
A manufacturer’s representative shall be present on site for the initial start of the installation
of the interlayer reinforcing grid
3.5 PROTECTION
A.
Protect installed product until completion of project.
B.
Repair or replace damaged products before Substantial Completion.
END OF SECTION
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