Asphalt Pavement Magazine - January/February 2013 - (Page 24)
A small amount of material is milled off the street prior to the overlay to smooth out bumps from old utility cuts.
The thin overlay restored a smooth ride to 10th Avenue North.
A New Hit in
hen the National Pavement Preservation Conference on (NPPC) came to Nashville in August, the pavement industry learned a new version of an old hit — thin asphalt overlays. Like a lot of popular music, people recognize the tune, but they don’t know all the lyrics. With asphalt, the lyrics center on the different mix types. The all-purpose standard, dense-graded mixes everyone thinks they know so well; the hard-rocking stone-matrix asphalt (SMA) riffs for the heavy traffic crowd; and the quiet chords of open-graded friction courses for those rainy day blues. Whatever the situation, asphalt has charms to soothe the savage breast. When thin asphalt overlays are used for pavement preservation, these different asphalt mixes come together like instruments in an orchestra. Thin overlays for pavement preservation are quite flexible and adaptable. The mixes can use a variety
24 • View past issues online at www.naylornetwork.com/nap-nxt
Nashville Demonstration Project Highlights Benefits of Thin Asphalt Overlays for Pavement Preservation
By Kent Hansen
of aggregate sizes — from 4.75 to 12.5 millimeters, depending on the thickness of the overlay. The aggregates can also vary in friction and quality requirements depending on location and traffic. There are a variety of asphalt binders available for different environments and traffic conditions. Recycled materials, such as reclaimed asphalt pavement (RAP), recycled asphalt shingles (RAS), and ground tire rubber, may be incorporated to reduce costs and improve environmental sustainability without compromising performance. So when we talk about thin overlays, we are really talking about a symphony of solutions for any pavement condition. Thin asphalt overlays, like all preservation treatments, are designed for use on pavements that are structurally sound and in good condition. In some cases, when a road is only in fair condition, for example, the existing surface may be milled to improve ride quality and remove surface distresses for improved performance.
Table of Contents for the Digital Edition of Asphalt Pavement Magazine - January/February 2013
NCAT Test Track Goes Straight
A New Hit in Music City
PennDOT Puts Innovation to Test
Roadway Safety+ Helps Reduce Injuries
The World of Asphalt Arrives in San Antonio
Get Ready to Grow
Focus on EH&S Excellence
Calendar of Industry Events
Index of Advertisers/Advertisers.com
Asphalt Pavement Magazine - January/February 2013