Page 57 - Green Builder Magazine Spring 2018 Awards Issue

Right in place. Cold-in-place recycling
finds a second use for the asphalt
used to patch highway roads.

CREDIT: NATIONAL PARK SERVICECHRIS WONDERLY

Asphalt Hits the Road Again

HEN IT COMES TO ASPHALT and road surface and strength while minimizing expenses typically
recycling, it’s not just roong tiles on the incurred during the paving process. In addition, CIR can correct
public’s minds. Cold-in-place recycling deep asphalt defects such as rutting, fatigue (alligator) cracking,
(CIR) is something you may not be and utility cuts that cannot be addressed by a surface treatment
W familiar with unless you’re in the road- or an overlay. It also allows minor corrections to the prole of a
building business. But it’s a term you should know. According road surface and reduces re–ective cracking, while posing only
to†Healthy Building Network, CIR, the rarest form of asphalt a minor inconvenience to tra•c.
pavement recycling, can reduce carbon dioxide emissions by as As its name implies, this is a cold process that requires
much as 95 percent per lane mile and can save as much as 40 minimal additional heat during rejuvenation of the asphalt
percent compared to conventional techniques. More-common material. This decreases the amount of energy required to
warm mix asphalt can reduce carbon dioxide†emissions by 15 produce the nal product.
percent compared to conventional paving. It also extends road life. According to a Federal Highway
CIR is a method of removing and reusing the existing asphalt Administration study for New York State, a CIR with a 1.5-inch
surface. It involves grinding o’ the top 2 to 5 inches of the overlay is expected to last 10-15 years, with little maintenance,
existing asphalt surface and mixing the crushed asphalt with an compared to the 5- to 8-year lifespan of a traditional 1.5-inch
asphalt recycling agent, and placing it back down with a paver. overlay. GB
Often, specic-sized aggregate is added to correct deciencies
found in the existing asphalt material. Excerpted from the Cornell University article, What is Cold-in-
By restoring and reusing existing material, less outside product place recycling and what are its advantages?
needs to be hauled to the worksite. This e•ciently improves the (www.clrp.cornell.edu/q-a/077-cir.html).

www.greenbuildermedia.com Special Awards Issue 2018 GREEN BUILDER 55

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