Equipment World Digital Magazine
Issue link: http://read.dmtmag.com/i/548484
EquipmentWorld.com | August 2015 63 term solution," he says. "Dealing with preservation is the biggest challenge for pavement managers. They just have more preservation work to do." Hickey says the additional chal- lenges of aging roadways coupled with long-term budget reductions have taken their toll on pavement managers, causing them to seek better preservation solutions. "The general feeling in the pavement management community is that seal treatments are not providing the ideal benefi ts," he says. "They don't extend structural life." Because DOTs have been so focused on creating long-life pave- ments, Hickey says his group has been promoting how thinlays can achieve this goal. "We tout the benefi t that you can get to a perpetual pavement 1 inch at a time," he says. "With our growing preservation needs and people looking at more life cycle cost concepts and preserva- tion, we're moving away from 'Oh, I've got to do some sort of pres- ervation, let me just throw some money at it.'" But like Fuller, Hickey stresses that thinlay application isn't a silver bullet, and contractors cannot ap- ply a thinlay on a structurally failed road and expect it to endure. And other times thinlay ap- plication mistakes may be due to confusion over the difference between a thinlay and a thinlift. "We can't just equate thinlift with thinlay," Hickey says. Thinlifts are standard mix designs placed thin; thinlays have a com- pletely different mix design. "Even in the asphalt community there's some confusion, and it's a mistake I regularly see. From a design and engineering standpoint, it's differ- ent." Hickey references the specifi c differences of smaller aggregate size and the softer binder grade. Softer binders are more crack resistant, whereas stiffer binders, which are used in thinlifts, are more suscep- tible to cracking. Roadway preparation The condition of a pavement is the fi rst consideration when deciding to use a thinlay (see sidebar), but the main way to ensure long-term Success and Failure Proper pavement conditions make the difference between thinlay success and failure Not every pavement condition is ideal for applying thinlays. Here's a breakdown of where they should and should not be used. • Shallow rutting, less than or equal to 1/2-inch deep • Top-down cracking • Block cracking (when sealed fi rst) • Less than 20 percent moder- ate fatigue cracking (when spot repaired fi rst) • Limited vertical clearance or curb reveal • Longitudinal cracking in vehicle wheel path • Overlaying widened sections • Transverse cracking (not thermal) • Raveling • Highly oxidized surfaces • Polished surfaces • Widespread deep rutting of more than 1/2-inch deep • Surface cracks wider than 3/8 inch • Deep patching more than 4 inches deep • More than 20 percent moderate to severe alligator cracking • Potential layer debonding or subsurfacing stripping areas • Severe bleeding/fl ushing Acceptable thinlay conditions Unacceptable thinlay conditions With equipment maintenance software that will turn a chaotic shop into an effi cient operation. Take control of your shop... § Preventative maintenance scheduling & alerting § Work order & time card management § Mechanic planning & scheduling tools § Parts inventory control & analysis § Fuel & fl uid tracking § Skills & certifi cation management § Low risk—Software comes with a 12-month money back guarantee! 1-800-683-3196 | www.HCSS.com