Ultra Thin Lift HMA Best Practices

• Ensure ultra thin lift is rolled quickly after application. Because of the thin application, the mixture cools quickly and must be rolled in a timely fashion to achieve density and prevent early raveling.

• Using combination treatments extends the service life of the pavement verse a stand alone ultra thin lift asphalt and allows you to use this application on pavements with lower PCI ratings (C 55-70).

• Ultra thin lift applications are not intended to be a layer to prevent reflective cracking. Larger cracks should be crack sealed prior to the application of an ultra thin lift treatment.

• Use of a shuttle buggy and warm mix technology will increase time availible for compaction and help ensure a successful project.

• Ultra thin lift mixes are great options for use as a leveling or scratch course.

• Allow the mat to cool prior to opening to traffic.

• When projects occur within home owner's assocations, working with the HOA president or management team is an excellent way to spread the word about upcoming projects.

• On roads with an uneven surface or profile, it may be necessary to mill the existing pavement prior to application. Milling can eliminate the surface distresses and allows the mix to be tied into existing gutter pans and utilities. By creating a level pavement, milling can help achieve the desired thin application rate, which can vary significantly on uneven road surfaces.

• Ensure crack sealing material applied prior to ultra thin application is not excessive and is applied flush with the existing pavement.

• Warm mix asphalt technologies will increase workability and compactability of treatment.

• Due to the thinner application, ultra thin lifts have a tendency to debond at a higher rate than traditional mixes. It is very important to ensure the existing pavement is thoroughly cleaned prior to application.

Because the overlay is thin, the interface between the old and new pavement is in close proximity to the shear forces created by vehicles during braking and turning movements.  As a result, the tack coat is extremely important to the long term success of ultra thin lift asphalt. The tack coat creates a bond between the new surface and the old pavement.