Ultra Thin Bonded Wearing Coarse

Sponsored by: Minnesota LTAP Center

Presented by: Michael Marti, P.E.SRF Consulting Group, Inc.

Dan Wegman, P.E.SemMaterials

A little history. . .

• 1988 - First Trial in France• 1992 - Introduced in U.S• 1992 - Jobs in TX & AL• 1993 - Jobs in NJ & PA• 1999 - Jobs in MN

Ultra Thin Bonded Wearing Coarse

What is it?• Surface Treatment

– Preventive Maintenance– Corrective Maintenance (Surface Rehabilitation)

• Single Pass System– Emulsion membrane– Thin gap-graded hot mix – Placed with Special Equipment

3 ProcessesSpray NovabondLay Hot MixSmooth the Mat

Ultra Thin Bonded Wearing CoarseMachine Specially Engineered

Application of membrane

Application of HMA

Ultra Thin Bonded Wearing Coarse: The Process

Existing Pavement

Surface of Mix

3/16”Membrane

Coating on mix3/8” Agg

Size

Total 9/16” Depth of Mix

The Novabond Cures, Bonding the HMA to the Pavement

Polymer Modified Membrane

• Sprays easily• Cures quickly• Superior bonding

Ultra Thin Bonded Wearing Coarse HMA

• High quality aggregate– Restores & retains friction

• Gap-graded– Reduces noise– Reduces backspray

• Mix designed specially for process

Ultra Thin Bonded Wearing CoarseBinder

• Polymer modified binder – Less draindown– More forgiving (less sensitive to temp, etc.)– Quicker traffic return– Sticks better, less water sensitivity– Better cracking resistance– More durable

Application rates

• Emulsion membrane– 0.15 - 0.3 gal/yd2

• Ultra-thin hot mix asphalt overlay– Type A - 45-55 #/yd2– Type B - 50-65 #/yd2– Type C - 55-80+ #/yd2

• Total thickness: 3/8 to 3/4”

Rolling & Return to Traffic• Rolling only to seat aggregate• Return to traffic in 10-20 minutes

Ultra Thin Bonded Wearing Coarse Construction Advantages

• Quick to apply• Reopens to traffic quickly • Cost effective

Performance• Resists wear & rutting• High skid resistance• Reduced tire splash, hydroplaning• Reduced tire noise• Seals out water• No loose aggregate• Thinner lift

– reduces applied weights – overhead clearance, curb reveal & drainage profiles– maximizes use of expensive aggregates

Reduced BacksprayWisconsin project - 5000 ADT

Backspray from dense graded surface

Greater visibility on Ultra Thin Bonded Wearing

Coarse surface