For Condition Level:
PCI:

70-80

What’s this?

This indicates the pavement condition for this treatment.

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Modified Chip Seal

Overview

Learn about the benefits of Modified Chip Seal Treatments

A modified chip seal extends the serviceable lifetime of roadways in low to medium distress situations. With a polymer-modified asphalt binder as a base, a modified chip seal is ideal for superior aggregate retention that allows for a quick return to traffic.

At an average cost of $2.35 per square yard, the use of a modified chip seal extends the life of a roadway by roughly 6-7 years.

Modified chip seals can be used to prevent or repair areas of oxidation, top down fatigue cracks, raveling or loss of friction. However, they are not recommended for unsealed cracks larger than ¼” or ruts deeper than ⅜”. The benefits of modified chip seals are not limited to preservation, as they can also be used to update a gravel road to a paved road.

Gansberg completed research on the many different types of binders and sealers used for roadway preservation. He found that modified chip seals were ideal for roadways with medium to high daily traffic volume as they were found to be less likely to break down under higher stress due, in part, to the modified aggregate binder.

Best Practices

  • Follow a prepared design.
  • Seals cracks larger than ¼”.
  • Use a single size clean stone.
  • If necessary, make adjustments to target rates depending on field conditions.
  • Calibrate all equipment. Do not over apply aggregate.
  • All traffic, including construction equipment, should be controlled to less than 35mph until final sweeping.

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