Airfield Pavements

Published by the Government Accountability Office on 1997-02-27.

Below is a raw (and likely hideous) rendition of the original report. (PDF)

GAO     United States
        General Accounting Office
        Washington, D.C. 20548

        Resources, Community, and
        Economic Development Division                                                     J582 1 5


        February 27, 1997

        The Honorable John McCain
        Chairman, Committee on Commerce,
         Science, and Transportation
        United States Senate

        Subject: Airfield Pavements: Use of Sealer/Rejuvenators to Extend the Life of

        Dear Mr. Chairman:

        Since 1989, 77 airports have used coal tar-based pavement products to
        rejuvenate and prolong the life of aging pavement and seal it against fuel spills.
        Thirty-six of these airports received grants under the Federal Aviation
        Administration's (FAA) Airport Improvement Program (AIP) to pay for the
        work.' Concerns have been raised that some of these sealer/rejuvenator
        products may not comply with FAA's guidance-Engineering Brief 44 (EB-44)-on
        the material content of, physical properties of, and the requirements for coal tar
        and coal tar oils in the products. 2

        This report responds to your request that we determine (1) whether the
        sealer/rejuvenator products used on federally funded projects comply with the

         The database for FAA's Airport Improvement Program does not always differentiate sealer/rejuvenator
        projects from other pavement rehabilitation projects. Therefore, we were unable to derive from the
        database an accurate total dollar amount of federal funds spent on sealer/rejuvenator projects.

         FAA's guidance on the use of pavement sealer/rejuvenators is contained in Engineering Brief 44, issued in
        November 1989. FAA's engineering briefs provide information and guidance regarding materials that may
        be used on federally funded airport projects. EB-44 provides a general outline for the use of pavement
        sealer/rejuvenator products.

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guidance in FAA's EB-44 and how FAA ensures that sealer/rejuvenator products
comply with EB44 and (2) what has been the experience of airports in using
these products.


Independent laboratory test results conducted for airports and us showed that
sealer/rejuvenator products used on federally funded projects comply with
FAA's guidance. In monitoring compliance with this guidance, FAA does not
conduct its own independent tests of these products or validate that such tests
have been done. Instead, as with other products approved for AIP funding, FAA
relies primarily on the airports to ensure that the products meet FAA's
guidance. On the basis of our survey of all airports using federal funds during
the period fiscal year 1989 through fiscal year 1996 for sealer/rejuvenator
products, all airports provided such assurances to FAA mainly through
certifications obtained from the manufacturers.

Our survey found that airport officials report general satisfaction with
sealer/rejuvenator products to date, but the actual performance test results of
the products' effectiveness are limited. As general guidance, EB-44 does not
provide airports with an indication of the degree to which the products should
repel spilled fuel or enhance the life of pavements but, rather, an indication of
what the products should contain. FAA acknowledges the limitations of its
guidance and plans, in consultation with industry and airport officials, to issue a
general performance-based specification for sealer/rejuvenator products.


Airports use coal tar-based pavement sealer/rejuvenators to extend the life of
asphalt runways, taxiways, and aprons. When applied, sealer/rejuvenators are
meant to simultaneously seal and penetrate the pavement's surface; that is, part
of the sealer/rejuvenator material permeates the asphalt and restores its
flexibility, while the other portion remains on the surface to protect the
pavement against damage from fuel spills, air, and water.

FAA first allowed sealer/rejuvenator products to be eligible for AIP funding in
1989 after an Air Force study3 and data from a sealer/rejuvenator manufacturer
indicated that such products could have a positive effect on airport pavements.
The Air Force conducted its study to evaluate the effectiveness of rejuvenators
on aging military airfield pavements. The study provided some performance
data indicating that rejuvenators prolonged the life of pavements. However,
only one of the products currently available was available at the time of the
study. FAA also used other data provided by a sealer/rejuvenator manufacturer

 U.S. Army Engineer Waterways Experiment Station, Evaluation of Rejuvenators for Bituminous
Pavements (AFCEC-TR-76-3, Feb. 1976).

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that showed that the sealer/rejuvenator reconditioned the asphalt, thus
prolonging the useful life of the pavements.


The three sealer/rejuvenator products used on AlP-funded airport pavement
projects comply with EB-44's guidance. The guidance states that the product
shall have a certain material content, specific physical properties, and coal tar
and coal tar oils in the product. According to FAA officials, to demonstrate
compliance, a sealer/rejuvenator product must undergo a series of tests to (1)
determine the type of material used to create the product, (2) examine the
physical properties of the product (such as its specific gravity and its softening
point), and (3) ascertain that coal tar and coal tar oils are present in the
product. These tests can be performed either by the manufacturer or by an
independent laboratory on behalf of an airport. FAA does not conduct
individual product tests or certify that such tests have been done. Instead, as
with other AIP-funded projects, airport officials sign a series of grant assurances
as a condition of receiving federal funding for airport projects, including a
general assurance that policies, such as EB-44, are being followed. 5

To provide assurance that EB-44 is followed, airport officials typically rely on
manufacturers' certifications. 6 We surveyed 36 airports that had at least one
AIP-funded sealer/rejuvenator project completed from fiscal year 1989 through
fiscal year 1996 and found that in each case, the airport assured FAA that its
products complied with EB-44. According to officials at the 36 airports, all
airports used certifications provided by the manufacturers, but in addition, 4
airports conducted independent tests to check compliance.

To ensure that each product complies with FAA's guidance, we requested
independent test results from FAA, airports, states, manufacturers, and
engineering consultants that would determine the material content, physical
properties, and presence of coal tar and coal tar oils for each manufacturer's
product. If independent laboratory test results of a product were not available,
we obtained product samples from airport projects and coal tar manufacturers

 The three products are (1) CBRT-SO, manufactured by E.A. Mariani Asphalt Company, Tampa, Florida;
(2) CI-5, manufactured by Bitumen Supply, Inc., Houston, Texas; and (3) PDC, manufactured by KA.E.
Paving Consultants, Inc., Pittsburgh, Pennsylvania.

 AII airport officials must sign a series of grant assurances as a condition of receiving federal funds for
airport projects. The grant assurances are incorporated by reference into the grant agreement. FAA
requires that airport officials ensure that all airport projects will be carried out in accordance with
policies, standards, and specifications approved by the Secretary of Transportation, including-but not
limited to-the advisory circulars listed in the current FAA Advisory Circularsfor AlP projects.

    EB44 does not require airports to independently test the sealer/rejuvenator products.

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and submitted them to independent laboratories for assessment. (See encl. I for
testing information.) The independent laboratory tests showed that all three
manufacturers' products comply with EB-44.


Thirty-two of the 36 airports that used coal tar sealer/rejuvenators on AIP
projects during the period fiscal year 1989 through fiscal year 1996 reported
general satisfaction with the performance of the pavements following the
application of the sealer/rejuvenator products. 7 For example, the airport
manager at Lake Havasu City, Arizona, where sealer/rejuvenator products were
applied to the entire airfield in November 1995, said he was very pleased with
the performance. The airport manager said that routine airfield maintenance
costs have diminished since the application of the sealer/rejuvenator. According
to the manager, prior to the sealer/rejuvenator's application, many small
pavement particles on the airfield had to be swept off on a regular basis-now
the airfield rarely requires sweeping. The Chief of Airport Pavements, City of
Houston, Department of Aviation, said that he is satisfied with the performance
of sealer/rejuvenator products applied to several runways and taxiways at
Houston Intercontinental Airport. He said that the sealer/rejuvenator-treated
pavements appeared to have fewer new small cracks than untreated surfaces.

Three of 36 airports we contacted indicated that they had received some
complaints from businesses and residents around the airport about strong odors
associated with the application of certain sealer/rejuvenator products. 8 In one
case, an airport hired consultants to monitor the air quality during the
application of the sealer/rejuvenator; the consultant found no air quality
hazards. The Director, Airport Safety and Standards, FAA, said that FAA was
aware of complaints about odor during the application of certain
sealer/rejuvenator products. The Director said that, to the best of his
knowledge, the odor is unpleasant but not hazardous. According to the airport
officials at the three locations, the odor dissipated within hours of application
and did not affect airport officials' general satisfaction with the
sealer/rejuvenator products.

 The remaining four airports indicated that they were neither satisfied nor dissatisfied with the coal tar
sealer/rejuvenator products applied to their airfields. Officials from two of the airports-one that used
CBRT-SO and one that used PDC-said that since they had completed their sealer/rejuvenator projects in
the summer of 1996, it was too soon to tell whether the product would be effective on their airfields.
Officials at the third airport said that the sealer/rejuvenator applied to their airport-PDC-did not perform
as they had expected but noted that the product might have had an adverse reaction to prior pavement
treatments. Officials from the fourth airport said the sealer/rejuvenator-PDC-took too long to cure.

 Two of the airports that complained of a nuisance odor used CI-5; one of the airports that complained of
a nuisance odor used PDC.

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Most airports using sealer/rejuvenators had not measured the performance of
sealer/rejuvenators on their pavements and such tests are not required by FAA.
For those airports that did measure performance, the results were somewhat
mixed. For example, the Florida Department of Transportation Aviation Office
conducted an independent test at Dunnellon Municipal Airport that
demonstrated that the asphalt's rate of deterioration was temporarily reversed
on the sealed and rejuvenated pavements. The Missouri Department of
Transportation, Multimodal Operations Division, Aviation Section, conducted
studies at four airports using the same sealer/rejuvenator product. The studies
showed an improvement at two airports, no change at one airport, and an
increase in the pavement's brittleness at one airport. A study conducted for Rio
Grande Valley International Airport in Harlingen, Texas, on 30-year-old
pavement showed no improvement following the test application of a
sealer/rejuvenator product on the airfield.

We found no comprehensive independent tests comparing the performance of
the sealer/rejuvenator products of the three manufacturers. Sealer/rejuvenator
manufacturers provided us with test results showing that pavements were
improved after the product was applied. However, FAA has not verified the
accuracy or validity of these test results and continues to rely instead on data
presented in the 1976 Air Force study. The Air Force study's relevance is
limited in that it only included performance data for one of the three
sealer/rejuvenator products because the others were not introduced until 1995.

Airport officials and sealer/rejuvenator manufacturers expressed some concern
that the guidance included in EB-44 is not specific enough to ensure that all
sealer/rejuvenator products will be fuel resistant and rehabilitate the pavement.
The tests mentioned in EB-44 address a sealer/rejuvenator's content but not its
performance. For example, an engineer who is responsible for several airport
projects in New Mexico and Arizona said that guidance in EB-44 is so vague
that any number of products could demonstrate compliance. Moreover, the
engineer said that EB-44 does not provide any assurance that these products
will perform the dual task of sealing and rejuvenating the pavement.

Sealer/rejuvenator manufacturers stated that a product could meet the guidance
of EB-44 but may not be fuel resistant or rehabilitate the pavement in part
because of the composition of the individual products. EB-44 does not specify
the exact composition of materials to use when manufacturing the
sealer/rejuvenator product. However, some manufacturers believe the
percentage of coal tar oils contained in the product may affect its performance
on the pavement. Because of the disagreement over the guidance, most airport
officials and sealer/rejuvenator manufacturers agree that FAA should require
performance-based measures in any new specification that may be developed.
FAA agrees that EB-44 needs modification and has initiated the process of
preparing new guidance.

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In July 1996, FAA drafted and circulated a revised EB-44 but discarded it after
two manufacturers raised numerous concerns about the draft. As a result of
these concerns, FAA decided to issue a general, performance-based standard for
sealer/rejuvenator products. FAA held a meeting of all manufacturers of
sealer/rejuvenator products in September 1996 to obtain their input on a
proposed performance-based specification. The manufacturers agreed that the
new specification should measure performance through tests to show how
certain properties of the pavement change after the sealer/rejuvenator is

In November 1996, FAA sent a draft specification-one that included proposed
performance measures-to interested parties, including manufacturers and
airports, for comment. 9 The proposed performance measures specify, for
example, that certain changes must occur to a pavement within 24 hours after
the sealer/rejuvenator has been applied and be maintained over a 2-year period.
FAA plans to issue the final specification in the spring of 1997.


We provided the Department of Transportation with a draft of this report for
review and comment. We met with officials of the Department, including FAA's
Director for Airport Safety and Standards and the Manager of the Engineering
and Specifications Division, who said that the report accurately reflected the
facts regarding fuel resistant sealer/rejuvenators and EB-44.


We interviewed and obtained documentation from FAA officials in Washington,
D.C., and the Alaskan, Central, Eastern, Great Lakes, Northwest Mountain,
Southern, Southwest, and Western-Pacific Regions on pavement
sealer/rejuvenators and their use on federally funded airport projects. We also
discussed pavement sealer/rejuvenators with the state aviation departments in
Arizona, Florida, Missouri, New Mexico, North Dakota, and Texas. To verify
the sealer/rejuvenators' compliance with EB-44, we interviewed and obtained
documentation from all three product manufacturers. In addition, we obtained
product samples from airport projects and coal tar manufacturers and had them
tested by independent labs. (See encl. I.)

To ascertain whether FAA ensured that sealer/rejuvenator products comply with
EB-44 and to obtain information regarding the experience of airports using
these products, we conducted a telephone interview, using a standard set of

 The proposed specification will be issued as an amendment to Advisory Circular 150/5370-10A, "Standards
for Specifying Construction of Airports." FAA officials said that engineering briefs, such as EB-44, are
often used as guidance for new products. Once the products have been used successfully over a period of
years, FAA converts the engineering brief into a more permanent specification.

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questions, with each airport sponsor using sealer/rejuvenators on federally
funded projects. (See encl. II.) We obtained a 100-percent response rate from
the telephone interviews. In addition, we attended an FAA-sponsored meeting
of sealer/rejuvenator representatives to discuss a new performance-based
specification. We conducted our review from August 1996 through February
 1997 in accordance with generally accepted government auditing standards.

We are sending copies of this report to the Secretary of Transportation and the
Administrator, FAA. We will make copies available to others on request.
Please contact me on (202) 512-3650 if you or your staff have any questions
about this report. Major contributors to this report were Sarah Brandt, Dana
Greenberg, Stan Stenersen, Mindi Weisenbloom, and Randy Williamson.

Sincerely yours,

Gerald L. Dillingham
Associate Director, Transportation Issues

Enclosures - 2

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ENCLOSURE I                                                                             ENCLOSURE I


To respond to the first objective-to determine whether the sealer/rejuvenator products
used on federally funded projects comply with the guidance in the Federal Aviation
Administration's (FAA) Engineering Brief 44 (EB-44)-we sought indepenpendent test results
for each of the three sealer/rejuvenator products. To demonstrate its compliance with
EB-44, FAA officials said that a sealer/rejuvenator product must undergo a series of tests
to (1) determine the type of material used to create the product, (2) examine the physical
properties of the product (such as its specific gravity and its softening point), and (3)
ascertain whether coal tar and coal tar oils are present in the product. To obtain the
independent test results, we contacted airport officials at each airport that received
federal funds for a sealer/rejuvenator project to inquire if independent tests were
conducted on the product. In addition, we contacted FAA, manufacturers, engineering
consultants, and aviation departments in states that have used sealer/rejuvenator
products. We found limited independent test results available, as shown in table L1

Table 1.1: Available I      ndeent Tests on Sealer/rejuvenator Products

                                                                  Results of
                                                                  independent tests to
                Results of independent   Results of independent   ascertain whether
                tests to determine the   tests to examine the     coal tar and coal tar
                type of material used    physical properties of   oils are present in the
    Product     to create the product    the product              product
    PDC          No independent test     No independent test      No independent
                 results found.          results found.           test results found.
    CBRT-SO      Caldwell Industrial     Caldwell Industrial      No independent
                 Airport (Idaho), Apr.   Airport (Idaho), May     test results found.
                 17, 1996. Material      5, 1996. Material
                 met specification.      met specifications.
    Cl-5         No independent test     Lake Havasu City         No independent
                 results found.          Airport (Arizona.),      test results found.
                                         Nov. 13, 1995.
                                         Material met

In order to fully respond to the objective, we made provisions for the remaining
independent tests.


We requested that FAA and airport officials identify laboratories that could conduct the
three series of tests necessary to demonstrate compliance with EB-44. FAA and airport

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ENCLOSURE I                                                                                          ENCLOSURE I

officials suggested that we contact Chicago Testing Laboratory, Inc. (CTL). CTL had
performed tests for Caldwell, Idaho (see table 1.1 above) and was capable of conducting
two of the three series of tests necessary to demonstrate the products' compliance with
EB-44. The other labs that we considered were unable to perform the complete test and,
in two cases, would have subcontracted the test to CTL.' Therefore, we selected CTL to
(1) determine the types of materials used to create the product PDC and the product CI-5
and (2) examine the physical properties (such as the specific gravity and the softening
point) of PDC.

For the third series of tests-ascertaining the presence of coal tar and coal tar oils in the
product-airport and other laboratory officials suggested four laboratories (Calcoast
Analytical, Phoenix Chemical Laboratory, Professional Services Inc. (PSI), and Herguth
Laboratories, Inc.) 2; we selected Calcoast Analytical to conduct the coal tar analysis for
all three products. Calcoast Analytical used the distillation of the product, followed by
gas chromatography/mass spectroscopy to identify the compounds in the distillation
fraction to detect the presence of coal tar and coal tar oils.


We obtained product samples from actual airport projects to ensure that the products
were created for an airport project and not for analysis purposes alone. We selected
samples from airport projects at Sebastian, Florida (for CBRT-SO) and Ruidoso, New
Mexico (for CI-5 and PDC). The samples were procured by airport officials or their
consulting engineers. For the samples of coal tar obtained to determine the types of
materials used to create the products, we acquired manufacturers' certifications that the
samples provided directly by the manufacturers consisted of the same materials used to
make each product.

All of the samples were shipped to the labs following procedures for hazardous materials
of the Department of Transportation's Research and Special Programs Administration.
The samples were shipped in packaging that complied with federal guidelines, and each
shipment contained a material safety data sheet outlining the potential health hazards
associated with each product.

 Three other sources, Professional Services Inc.; Western Technologies, Inc.; and the Florida Department of
Transportation, State Material Office, had also conducted independent tests for airports or manufacturers. However,
none of these labs were able to conduct one of the tests (Engler viscosity) required to demonstrate compliance with the
physical properties requirements of EB-44.

  At CTL's suggestion, we contacted Phoenix Chemical Laboratory. A Phoenix Chemical laboratory official said that he
could determine the presence of coal tar and coal tar oils through chemical, physical, and spectrographic techniques.
PSI had previously done some coal tar analysis on one of the products, but a laboratory official said that PSI no longer
had the expertise to conduct this type of analysis. A laboratory official from Herguth Laboratories, Inc., said that her
lab would not do this sort of analysis on coal tar.

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ENCLOSURE II                                                                                    ENCLOSURE II


Airport                                      City                   State    Year       Product
1. Albany County                             Albany                 NY       1996       CBRT-SO
2. Ainsworth Municipal                       Ainsworth              NE       1994       PDC
3. Ann Arbor Municipala                      Ann Arbor              MI       1996       PDC
4. Bartow Municipal                          Bartow                 FL       1995       PDC
5. Brainerd-Crow Wing County                 Brainerd               MN       1992       PDC
6. Brazoria County                           Angleton               TX       1995       PDC
7. Burnet Municipal/Kate Craddockab          Burnet                 TX       1993       PDC
8. Caldwell Industrialb                      Caldwell               ID       1996       CBRT-SO
9. Cavern City Air Terminal                  Carlsbad               NM       1993       PDC
10. Central Nebraska Regional                Grand Island           NE       1996       CI-5
11. Clovis Municipal                         Clovis                 NM       1994       PDC
12. Corpus Christi International             Corpus Christi         TX       1994       PDC
13. Dexter Municipala                        Dexter                 MO       1993       PDC
14. Du Bois-Jefferson County                 Du Bois                PA       1989       PDC
15. Easterwood Field                         College Station        TX       1995       PDC
16. Ernest A. Love Fieldb                    Prescott               AZ       1993       PDC
17. Four Corners Regional                    Fam-ington             NM       1995       PDC
18. Gallup Municipal                         Gallup                 NM       1994       PDC
19. Greenbrier Valley                        Lewisburg              WV       1995       PDC
20. Houston Intercontinentalb                Houston                TX       1993       PDC
21. Jamestown Municipal                      Jamestown              ND       1996       PDC
22. Kansas City Downtown                     Kansas City            MO       1993       PDC
23. Kayenta                                  Kayenta                AZ       1996       CI-5
24. Lake Havasu Cityb                        Lake Havasu            AZ       1995       CI-5
25. Lincoln Municipal                        Lincoln                NE       1996       CI-5
26. Lordsburg Municipal                      Lordsburg              NM       1996       PDC
27. Morgantown Municipal                     Morgantown             WV       1995       PDC
28. New Braunfels Municipala                 New Braunfels          TX       1995       PDC
29. Pocatello Municipal                      Pocatello              ID       1993       PDC
30. Raton Municipal/Crews Field              Raton                  NM       1994       PDC
31. Robert Mueller Municipalc                Austin                 TX       1992/93    PDC
32. Santa Fe County Municipal b              Santa Fe               NM       1993       PDC
33. Scott City Municipal                     Scott City             KS       1993       PDC
34. Scotts Bluff County/Heilig Field         Scottsbluff            NE       1995       PDC
35. Sierra Blanca Regional                   Ruidoso                NM       1995       PDC
36. Wichita Mid-Continentc                   Wichita                KS       1992/93    PDC

a   Airport project funded under State Block Grant Program.

b   Indicates projects visited by GAO.

c Airport had more than one rejuvenator project funded with grants by the Airport Improvement Program.


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