In order to make the proper
sealant selection easy for your maintenance criteria and climatic
condition use the provided sealant selection guide link on this
page. This guide was developed by Crafco in conjunction with the
U.S. Department of Transportation. You will be able to determine
the type of preservation required, the type of product needed, and
the amount of product for the project.
The Federal Highway Administration
(FHWA) has completed one of the most extensive highway research
projects in history. The project known as LTPP (Long Term Pavement
Performance) had the goal of improving pavement design, pavement
performance and pavement preservation processes.
As part of this research, pavement temperature data from thousands
of locations across the United States and Canada were collected.
This information has been compiled in a database called LTTPBind.
This information is commonly used in the Super Pave binder selection
process.
Crafco has used this data to develop a product selection process for
sealant to be used in pavement preservation treatments. Coupled with
a treatment selection process you now have the ability to accurately
determine the right Crafco product, for the right process, for the
right pavement at the right time.
Product Selection Process
1- Evaluate pavement and determine pavement preservation treatment.
A) Crack Sealing
B) Performance Crack Filling
C) Joint Sealing
2- Determine pavement temperature
3- Select appropriate Crafco product for your application.
Step 1: Evaluating
Pavement
A) Crack Sealing : This process should be performed
on pavements that are in good condition. That is defined as a
pavement with a sound base and exhibits distress in the form of
thermal or working cracks with greater than 1/8 inch movement. The
procedure generally consists of sealing transverse cracks spaced 20
feet apart or more in order to prevent moisture from entering and
deteriorating the subbase and incompressible material from
interfering with thermal movement. See the Crafco Application
Instructions for your chosen sealant to get specific directions on
preparation and application. Generally, all crack seal operations
include mechanically widening the crack. The expected life of this
procedure is 5 to 9 years in most cases.
B) Performance Crack Filling : This procedure
consists of filling cracks with low (<1/8 inch) movement in order to
stop moisture from penetrating to the subbase of the pavement. If
moisture is not checked, catastrophic pavement failure such as
potholes will form. Another reason for crack filling is to stop
crack raveling. Crack filling is a very cost-effective method of
pavement repair that will add years to its life. Crack fill
pavements that are in fair to poor condition on a regular basis to
maintain or slightly improve their condition. A life of 6 to 8 years
can be expected in most instances.
C) Joint Sealing : The sealing of concrete pavement
joints is required to stop moisture from entering and deteriorating
the subbase of the pavement. The most cost-effective method of
ensuring optimum performance of a PCC pavement is by constructing a
sound joint seal system that will last. For detailed information see
the Crafco joint seal Product Data Sheet and Application
Instructions.
Step 2: Determine
Temperature Extremes
Find the area of the country you
are interested in on the map titled High Temperature on the
Evaluation Guide. The dot will correlate to a temperature zone
listed on the legend. For extreme traffic conditions (heavy, slow
moving, pedestrian, parking lots) when crack filling the high
temperature extreme should be increased one or two grades. Next,
locate your zone on the Low Temperature map. When this is done you
will have two Celsius numbers that represent a range of
temperatures. The hot or highest number is always first. Please note
that some of the -10°C areas on the low temperature map do not
actually get that cold, and will classify as a -4°C area. This can
be determined from the LTPPBind program.
Step 3: Select Crafco
Product
Using the temperature range numbers
determined in step one above, go to the Product Selection Grids
corresponding to the treatment process you selected in step two
above. These grids list the highly recommended products for specific
temperature ranges. There are letters listed in the cell correlating
to the hot and cold ranges you selected. Use the Product Summary
page to match the letters to a specific Crafco product. Many
products may also be used in other climates, as listed on the
Product Data Sheets. Use the Product Summary page to check the
specifications, and other characteristics such as if the product is
thick or thin or if it has any other unique properties. If you have
any further question your Crafco representative will be glad to
assist you.
For a more detailed explanation of the selection process, refer to
Crafco Product Selection Procedures, Product Data Sheets, and
Application Instructions. Items contained in the grids are the most
commonly used. Agency specified products are also available.
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Evaluation Guide < |