Alternative Pavements for Snowmobile Crossings14282D

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Alternative Pavements for Snowmobile
Crossings-14282D
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The Problem

• Snowmobile trails cross the highways
• Snowmobiles are equipped with accessories (studs
  and runners) for traction on ice
• Studs and runners made of carbide steel damage
  our highways by gouging the sand/asphalt portion
  of the asphalt mix
• WHY?

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Dynamics of Snowmobile Traction
Skis have a high drag coefficient on pavement
Small contact area of track studs offers little
traction, but erodes asphalt and sand from HMA
pavement during acceleration
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The Result?
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This,
And
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This,
And
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This,
And
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This,
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Snowmobile Track Studs

• Available in a variety of lengths
• Normal steel, or
• Carbon steel tips

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Snowmobile Track Studs
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Groomers

• The groomer and drag equipment length totals 40
  feet
• The equipment is heavy, 4 Tons for the groomer,
  2.5 for the Drag
• It crosses the highways
• Tracks are equipped with studs
• Skid steering causes damage due to high point
  loads and sliding

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Research Project Scope

• Locate trail crossings with differing levels of
  snowfall and snowmobile traffic
• Install two test products at each site
• Install 1/2overlay of a typical HMA as a control
  surface
• Monitor for two winters (now extended to three)
• Document visual changes (photos)
• Survey to measure wear compare with control
  areas
• Count sleds to evaluate impact of traffic level

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Typical DamageRoute 3 in Groveton

• SB shoulder gravel was eroded
• Pavement edge was broken from stud damage during
  snowmobile acceleration to cross highway.

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Typical DamageRoute 3 in Groveton

• Northbound shoulder gravel was eroded.
• Pavement edge was broken
• Pavement surface was worn from snowmobile studs.

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Regarding Edge Wear

• This type of wear is actually breakage due to
  erodion of shoulder gravel, exposed by plowing
  and de-icer action. It might be controlled by an
  apron extention leading 10 to 20 along the
  trail from the edge of pavement. This element
  was not a part of this project.

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Cleanosol (a.k.a. Nor.skilt)

• Thermoplastic product imported from Norway
• Applied to any clean, dry surface
• Heat material in kettle to 425o F
• Transfer to walk-behind applicator

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Installing Cleanosol

• Material is placed in 12 wide strips
• Strips are butted for smooth ride
• Researh project application went from pavement
  edge to crown

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Installing Cleanosol

• Applied in 3 layers
• Each layer offset to cover joint of previous
  layer
• Creates a tapered approach

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Installing Cleanosol

• Single strip along edge covers ends to complete
  installation

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Imprint

• Thermosetting resin-based compound of fine-graded
  granite aggregate, reinforced with 2 types of
  fibers
• Available in 12 colors
• Inlaid installation
• Heated in kettle to 400o F
• Typically used for crosswalks and traffic calming
  applications

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Installing Imprint

• Transferred to surface by bucket
• Applied by hand and spread with a heated 9 x 9
  iron
• Completed surface is covered with sand

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Installing Imprint

• Completed red installation in Rumney
• Gray installed in Errol and Groveton

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Product ComparisonsCleanosol
Imprint

• Installed by 2-man crew
• Simple preparation
• Constant thickness applied smooth finish
• Matched existing shape of surface
• Unit cost 18.00 / SF

• Installed by 3-man crew
• Inlay process requires more labor/cost
• Uneven surface/ride due to hand application
• Early cracking
• Unit cost 6 / SF

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Observations After First WinterCleanosol
Imprint
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Observations After First WinterCleanosol
Imprint
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Errol After Second WinterCleanosol
Control
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Errol After Second WinterImprint
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Findings To Date

• Both materials are at least as durable as the
  control surfaces. Wear patterns are similar.
• Imprint was not originally intended for this
  application. Higher cost and uneven surface were
  negatives.
• Cleanosol could be used for a trail crossing
  maintenance program
• Apply only after new pavement is damaged
• Re-apply as worn in heavy sled traffic areas
• Overlay as part of overall pavement program
• Edge breakage is an equal problem to surface wear.

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QUESTIONS?
Alan D. Rawson, P.E. Materials Engineer NHDOT
Bureau of Materials Research P.O.
Box 483, 5 Hazen Dr. Concord, NH
03302-0483 603-271-3151 arawson_at_dot.state.nh.us
SNOWMOBILING IS A DISEASE. THERE IS NO CURE.