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Introduction
The Amoco
Petromat® System extends the life of new asphalt concrete (AC) pavements and AC overlays. The Petromat System consists of Amoco's Petromat non-woven polypropylene fabric which is field saturated with an asphalt cement tack coat. When placed between pavement layers, the Petromat system becomes an integral part of the roadway section, forming a barrier to water infiltration and absorbing stresses to reduce reflective and fatigue cracking of the new AC surface layer. Since 1965, the economical Petromat System has had an outstanding record of improving pavement performance while reducing maintenance and roadway
life-cycle costs. Paving fabric systems are currently being used at a rate of over 15,000
equivalent lane miles per year in North America alone.
Benefits Moisture Barrier Function: The greatest source of damaging water in road structural sections is precipitation infiltration through pavements. Most pavements do not have adequate drainage systems to quickly remove infiltrated water. If a pavement base is saturated as little as 10% of the time, the useful life of that pavement will be reduced by 50%. The Petromat fabric, when saturated with the asphalt cement tack coat, becomes a moisture barrier in the pavement, minimizing surface water infiltration. The American Association of Highway and
Transportation Officials (AASHTO) 1993 flexible pavement design methodology gives a substantial structural credit to unbound roadbase materials when they are well drained and not allowed to become saturated. By minimizing water infiltration, the Petromat System moisture barrier will keep the road base more well drained and will therefore maximize the structural strength of unbound roadbase materials.
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Performance: Both laboratory and field testing have shown pavements to be 10 to 1000 times less permeable when the Petromat System is incorporated as an interlayer. A complete treatise on the need for pavement moisture control and the effectiveness of paving fabric systems as moisture barriers may be found as a Transportation Research Board
(TRB) Circular and is summarized as Tech Note 4 by Amoco Fabrics and Fibers Company. The circular, ECO06, may be found on the TRB web site as an online publication at
"http://www.nas.edu/trb/publications/ec006.html". Also shown in the referenced paper is the need for a uniform application of the proper amount of asphalt cement tack coat for the Petromat System to achieve the desired very low
permeabilities. 
Stress Absorbing Interlayer
Function: Petromat paving fabric, saturated with asphalt cement, forms a substantial interlayer media within which stresses can be absorbed. Stresses associated with limited movement along cracks and joints in existing AC or Portland cement concrete
(PCC) pavements are absorbed within the paving fabric system and therefore, are not translated, or reflected, up into the asphalt concrete layer over the system. If there is excessive movement of existing cracks or joints, there are more robust membrane interlayer products available,
such as, Petrotac®, Pro-Guard®, or PetroGrid™ for pavement treatment. Asphalt concrete flexible pavements will eventually develop fatigue cracking due to tensile stresses while flexing. The inclusion of the Petromat System interlayer results in a layered pavement with greatly reduced tensile stresses compared to monolithic pavements with no interlayer. The result is a dramatic increase in the fatigue life of new pavements or overlays. Performance: Laboratory simulation of comparable pavements both with and without the Petromat System interlayer indicated a 100 to 300% increase in the number of pavement load applications before fatigue or reflective cracking appeared over the Petromat System. Field performance indicates a 50 to 150% increase in overlay life before fatigue or reflective cracking occurs in overlays over the Petromat System versus control sections with no fabric. A comprehensive study, Maxim Technologies (1997), which examined available paving fabric research and empirical evidence, concluded that properly applied paving fabric systems, such as the Petromat System, equate to an additional 0. 1 to 0. 15 foot (3 to 4.4 cm) thickness of AC overlay for the retardation of reflective cracking. The study, which can be viewed at
"http://www.gmanow.com/techdoc/doc1.html/docindex.html", cited both the moisture barrier environmental benefits and the stress absorbing interlayer functions as the reasons for the success of paving fabric systems. Widespread field evaluations have verified the effectiveness of the Petromat System as shown below:
Petromat, Number One In The Business
Petromat, the original paving fabric, is the most widely used paving fabric in the world for the following reasons:
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Choice of Styles: Petromat styles 4598 and 4599 are the most widely recommended and used paving fabrics. Style 4598 meets the requirements of AASHTO guideline specification
M-288-96.
Cost-effective: The installed cost of the Petromat System(fabric and asphalt cement tack coat) is typically less than half the cost of 0. 1 foot (3cm) of AC. For extending pavement life, the installation of the Petromat System is therefore much less expensive than placing additional asphalt concrete or increasing roadway maintenance, Use of paving fabrics generally yields a savings in pavement rehabilitation system costs of more than $7,000 per lane mile.
Versatile: The Petromat System is effective within new AC pavements, below AC overlays over rigid and flexible pavements, and below surface
treatment(chip-seal) pavements. It can improve the performance of highways, city streets, parking areas, airport pavements, bridge decks and other pavement surfaces.
Made by Amoco: A pioneer in the paving fabrics and
geotextiles, Amoco provides customers with quality products, a wealth of technical information and assistance, and the nation's most extensive and knowledgeable distributor network. If you have any questions or need
technical assistance, please call us at 800-445-SPEC (7732).
Installation
Detailed information on installation of Petromat paving fabrics can be found in the Amoco
Petromat Installation Guide.
Published Reports
Majidzadeh, K., A Laboratory
Investigation of Use of Petromat for
Optimization of Pavement Performance, Ohio State University, Nov
1976.
State of California, Evaluation of Paving Fabric Test
Installations in California, Report No. FHWA/CA-90/02, CALTRANS, Department
of Transportation, Feb. 1990.
State of Florida, Reduction of Reflective Cracking in Biturminous,
Overlays, Payne's Prairie Experimental Project Florida Department
of Transportation, Office of Materials & Research, Research
Report 176-A, State Project: No. 26260-8426, June 1977.
State of New Mexico, New Mexico Study of Interlayers Used in
Refleclive Crack Control, New Mexico State Highway Department
Research Report MB-RR-84/1, Sept 1984.
State of Oklahoma, The Evolution of Non-Woven Fabrics, Oklahoma
Department of Transportation, Research & Development Division,
Report No. FHWA/OK 82(6), May 1982.
State of South Carolina, Evaluation of Petromat When Used With Bituminous Surface Treatment, South Carolina Department of Highways & Public Transportation, Research & Materials laboratory, In-House Study 82-5, Dec. 1990.
State of Texas, Overlay Construction and Performance Using
Geotextiles, Texas Transportation Institute, Texas A&M University System, Paper No. 880424,Jan.1989.
State of Virginia, Control of Reflection Cracking in in a Fabric-Reinforced Overlay on Jointed Portland
Cement Concrete Pavement, Virginia Highway & Transportation Research Council,
VHTRC: 83-R8, Aug. 1982.
City of Verdun, Quebec Canada, Pavirs Road in Severe Canadian Climate, Oct. 1995.
Maxim Technologies, Inc., "Nonwoven Paving Fabrics Study" for I industrial
Fabrics Association International, Oct. 1997. http://www.gmanow.com/techdoc.htm/docindex.html
Marienfield, M. L. and Baker,
T.L., Paving Fabric interlayer System as a Pavement Moisture Barrier, Transportation Research Board Paper # 9881112, 1998.
http://www.nas.edu/publications/ec006.html
Note: This brochure is believed to be an accurate representation of information available from public sources; however, because the conditions in which such information may be used are beyond the control of Amoco Fabrics and Fibers Company, Amoco does not guarantee the suggestions and recommendations contained herein. Amoco assumes no responsibility for the use of information presented herein and herby disclaims all Iiabilities which may arise in connection with such use. Final determination of suitability of information and suggested uses is the sole responsibility of the user. Petromat is a registered trademark of paving fabrics manufactured by Amoco Fabrics and Fibers Company.
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