37th Annual Rocky Mountain Asphalt Paving Conference February 25, 2010 Greg Milburn

WAR ON CRACKS New Generation Paving Fabrics 37th Annual Rocky Mountain Asphalt Paving Conference February 25, 2010 Greg Milburn

Overview What causes cracks Why treat cracks Which cracks to treat Preventative crack reflection techniques Crack sealing/crack surfacing Paving Fabric SAMI (Stress absorbing membrane interlayer) Sawed relief joints

at causes cracks Overview y treat cracks ich cracks to treat ventative crack reflection techniqu rack sealing/crack surfacing aving Fabric AMI (Stress absorbing membrane nterlayer) awed relief joints

What Causes Cracks Thermal expansion/contraction (working) Change in HMA volume due to temperature changes Fatigue (non-working) Longitudinal wheel path Alligator Age hardening/oxidation of binder

Why Treat Cracks? Cracks are inevitable and neglect leads to accelerated cracking and potholing, further reducing pavement serviceability. (FHWA-RD-99-147)

Prevent water/incompressible intrusion Extends pavement life Can delay more expensive rehabilitations Protects base/subbase layers Original cracked AC

Prevent water/incompressible intrusion Extends pavement life Can delay more expensive rehabilitations Protects base/subbase layers New AC overlay Original cracked AC

Glass Fiber Reinforced Paving Fabric Fiberglass grid bonded to a non-woven paving fabric For use in repair of both flexible & rigid pavements Provides moisture barrier High strength at very low strains Asphalt binder applied: 0.23-0.28 gal/sy

Glass Fiber Reinforced Paving Fabric If application on milled surface 1/4 inch difference between adjacent ridges & valleys Difficult to install around tight radii May be problematic if milled Approximate tensile strength: 500 lbs/in ultimate & 300 lbs/in @ 2% strain Approximately 5 $/sy (installed)

Glass Fiber Reinforced Paving Fabric

Asphalt Reinforcement Grid Fiberglass grid For use in repair of both flexible & rigid pavements Not for use on milled surfaces High strength at very low strains Drainable Pressure sensitive adhesive or lightweight scrim

Asphalt Reinforcement Grid

Polyester/Fiberglass Paving Mat Non-woven matrix of Fiberglass & polyester fibers For use in repair of both flexible & rigid pavements Provides moisture barrier Non-shrink, non-stretch, high melt temperature

Polyester/Fiberglass Paving Mat Asphalt binder applied: 0.18-0.25 gal/sy If application on milled surface 1/8 inch difference between adjacent ridges & valleys Millable & recyclable Approximate tensile strength: minimum 100 psi Approximately 2 $/sy (installed)

Polyester/Fiberglass Paving Mat

Paving Fabric Challenges Choosing the right fabric for the job Use manufacturer s application charts Type of cracks? Waterproofing?

Paving fabric challenges Proper Installation Ensure Manufacturer's representative is present during installation

Paving Fabric Challenges Specification Development Permissive or prohibitive Developing performance based specifications

Sawed Relief Joints

Sawed Relief Joints Used on full-depth asphalt pavements Increases frequency of thermal cracks Minimizes joint movement from pavement temperature cycling Cracks/joints are more easily maintained Ensures smooth ride

QUESTIONS