Engineered fog sealers shall meet the requirements in the contract documents of the Iowa Department of Transportation. Approved brands of Engineered fog sealer are listed in the Materials Approved Products Listing Enterprise (MAPLE).



Properly identified and certified materials may be incorporated into a project. Final acceptance will be based on the certifications and the results from project verification tests and/or in accordance with special requirements when specified.  Project samples with noncompliant test results may require additional tests.



Request for approval shall be made in writing to the Office of Construction and Materials in Ames, Iowa. Include the following:

1.    A complete product description

2.    Manufacturer’s material specifications

3.    Manufacturer’s recommended application rate (gallons per square yard)

    1. Rate for paved surfaces in good condition
    2. Rate for paved surfaces in poor condition
  1. Submit test results from an accredited laboratory demonstrating all performance criteria is achieved. Submit a sample of at least one quart to the Central Materials Laboratory. Engineered fog sealers shall be approved prior to application on a project.


The application rate will be product-specific. Field application will use the published rate and may be adjusted by the Engineer based on test strip results.


Approval of suppliers will be based on compliance with the following requirements:


A.   Acceptable Control Laboratory


A control laboratory will be considered acceptable if it shows that test results can be obtained within precision limits established by AASHTO for each test. Precision will be judged by comparison with results obtained by the Central Laboratory in Ames. Laboratory facilities and procedures may be inspected and reviewed by Highway Division personnel.


Submit a minimum of two samples of each product in regular production annually to the Central Laboratory in Ames. Complete sample identification and supplier test results for all specified tests must be submitted for each sample. A comparison of the Central Materials Office test results with the suppliers’ test results will be made.


B.   Acceptable Quality Control Program


The supplier shall submit an outline of the Quality Control Program showing testing frequencies, tests performed, and a typical test report to the Office of Materials. Submit annual updates to the Central Laboratory.


C.    Performance Testing


When applied to a pavement at least 3 years old, the material shall physically change the properties of the asphalt binder contained within at least ¼ inch from the surface (or deeper).


Road Cores Testing

Apply the recommended rate of sealer to the surface of the road core and wait at least 10 minutes. Slice the top ¼” portion of the treated specimen and extract and recover the binder. Analyze the complex shear modulus viscosity, softening point, penetration, residual polymer content, and ductility. Repeat the recovery and analysis on companion road cores that have not been treated and compare the results.


D.    Retroreflectivity Retention


Once material properties are confirmed to be compliant, complete one of the following:

a.    The Central Materials laboratory will apply the material at a rate of 0.020 gal/SY to a sample of approved fast dry waterborne traffic paint. Using Iowa Test Method 918, the luminance of the paint will be compared to that of the paint and sealer. Retain a minimum 97% of the paint’s reflectivity.

b.    Submit retroreflectivity (before and after) results from a field project to demonstrate compliance with the project specifications at the recommended application rate.


E.    Friction Testing


Once material properties and retroreflectivity retention requirements are acceptable, it shall be responsibility of the submitting party to demonstrate the product does not excessively reduce pavement friction. Arrange a pavement location off of the primary system where the product can be applied at the recommended rate. The application must be in the driving lane where speeds of at least 40 mph may be maintained for at least 1000 feet. Prior to sealing, contact the District Materials Engineer to schedule ribbed-tire friction testing. Ensure the sealed pavement has a minimum friction value of 40 when measured per ASTM E274 at 40 mph. Measurements shall be taken no more than 30 days after the pavement is sealed. It is the responsibility of the contractor to confirm availability of testing crews with the DME to ensure the 30-day testing window is achieved. When possible, the Agency will perform testing before and after the sealing work is completed. In lieu of ASTM E274, ASTM E-1911 may be used on laboratory fabricated specimens.


F.    Records & Documentation


A satisfactory program for storage of test reports and shipment records shall be maintained. This program shall enable proper identification and documentation of all shipments made to projects and shall include a file of refinery test reports covering all asphalt binders.


Continued approval of a source will be based on the following:


A.   Ability to consistently supply material meeting specifications


B.    Ability to meet precision limits for testing.


C.  Continuation of originally approved Quality Control Program.


D.  Maintenance of required records


E.   Proper documentation of shipments


Approval to deliver certified material may be withdrawn for inadequate compliance with these requirements.



Monitoring activities of suppliers, including inspection of test reports, quality control records and procedures, and shipping records will be conducted by the appropriate District Materials Office.


All District Materials Office monitoring activities shall be reported to the Central Materials Office.



Each shipment invoice covering certified materials delivered to a project shall have a signed certification statement as to product name, specific gravity or weight per gallon (liter), quantity in load, batch number or other identification, project number, and compliance with the appropriate Iowa Department of Transportation Specifications. A copy of this invoice shall be furnished to the Contracting Authority at the time of delivery.


A supplier receiving material shall promptly obtain a report of complete test analysis covering each batch or identifiable lot received.