Crack Treatments
What Are Crack Treatments?

What are Crack Treatments?

CODE: A175
TITLE: Recommended Performance Guideline for Crack Treatment
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Crack treatments consist of placing specialized materials into prepared cracks to prevent moisture intrusion into the cracks and underlying pavement layers. Restriction of water entry into underlying pavement base and sub-grade layers serves to maintain pavement strength and prolong pavement life. Pavements in different climate zones, different construction types, and different traffic loadings experience different types of cracking. Different types of crack treatment materials and installation geometries are required for the different conditions.

There are several types of materials used for crack treatments ranging from unmodified asphalts and emulsified asphalts to polymer and rubber modified asphalts. Hot applied rubber and polymer-modified asphalts are the most widely used materials. Crack treatment materials must have appropriate properties for the climate in which they are used and need to be able to accommodate expected movement. Proper materials are available for use in all climatic areas.

Crack treatment materials can be installed in a range of configurations and with varying preparation methods. Configurations range from filling unprepared cracks and capping with a narrow over band, to specifically designed reservoirs that widen the crack to provide the correct geometry for the expected movements.

The first step is to examine the pavement to determine the cracking type, extent, and severity. This examination indicates if the pavement is an appropriate candidate for crack treatment and indicates the type of treatment method to use. Generally, pavements with low and moderate severity cracking are the best candidates. Crack treatments may not be appropriate for pavements with high amounts of severe cracking.

Crack Filling — Filling treatments are used for pavements that primarily have non-working cracks (less than 1/8-inch annual movement). Filling treatments generally consist of cleaning the cracks and placement of appropriate material in a fill and slight over band application. Filling treatments are generally used for cracks spaced at less than 20 feet for block cracking, random closely spaced thermal cracking, and longitudinal cracking.

Crack Sealing — Crack sealing treatments are used for pavements that primarily have working cracks (greater than 1/8-inch annual movement). Sealing treatments consist of creating a widened reservoir to provide proper geometry and placement of flexible, extensible material that can accommodate the expected movements. Sealing treatments are generally used for thermal cracking spaced at over 20 feet. For all sealing or filling installations, the treatment material needs to have appropriate properties for the specific temperature ranges at the project site.

Application consists of 3 basic steps– cleaning the cracks, cutting the reservoir if needed, and installing the material. Cleaning is generally accomplished using compressed air. Reservoir cutting is performed using a crack saw or router that can cut varying widths and depths as required. Hot applied products heated to the appropriate temperature in a Mettler unit equipped with agitation and a temperature monitoring device. The heated material is then pumped into the crack or placed using pour pots or wheeled applicators. Cold applied materials can be installed using pour pots, or other containers. For all installations, cracks must be clean and dry for the best performance.

Properly designed and installed crack treatments have been proven to last between 5 and 7 years.

Properly designed and installed crack treatments have been proven to increase pavement life up to 7 years.