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Sustainable Accessible Sustainable Accessible Trails Using Crusher Trails Using Crusher

Fines Fines Presented by:Presented by:John KowaleskiJohn KowaleskiTrailTechTrailTech LLCLLC

jkowaleski@trailtechllc.comjkowaleski@trailtechllc.comwww.trailtechllc.comwww.trailtechllc.com

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In this presentation I will illustrate why crusher fines are a good material to consider when constructing accessible trails. However, it is important to understand the nature of this material and how to correctly apply it. Otherwise, done the wrong way in the wrong location, you can lose your trail material.

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Crusher Fines Are…Crusher Fines Are…..

►►A byproduct of the rock crushing process, A byproduct of the rock crushing process, ground to specifications.ground to specifications.

►►Hard, angular particles, a mixture of Hard, angular particles, a mixture of aggregate and fines, typically 3/8” minus in aggregate and fines, typically 3/8” minus in size with a full spectrum of fines.size with a full spectrum of fines.

►►Vary in stone type, color, and size.Vary in stone type, color, and size.

Crusher fines are considered a soft surface. Crusher fines can consist of igneous rock, like traprock in my area, granite, or limestone. I always say, “The harder, the better.” Use your local rock quarry to make it economical.

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Firm and Stable Crusher Fines SpecsFirm and Stable Crusher Fines SpecsSieve Analysis: % PassingSieve Analysis: % Passing

Particle Size % of Passing

3/8" 100%

#4 90 - 100%

#8 55 - 80%

#16 40 - 70%

#30 25 - 50%

#200 6 - 15%

Composition is about half fines, half aggregate. These fines interlock together forming a hard firm surface. If the surface of the trail becomes loose and uncompacted over time it can often be reshaped, wetted and compacted again, (as long as the fines have not sifted to the bottom and the larger particles floated to the top). “3/8 minus is used also because if the surface unravels, the small aggregate does not interfere with access versus a larger material.Poor compaction can be the result of a variety of influences such as: lack of fines to bind particles together, over raking, improper wetting and compacting, lack of angularity, lack of precipitation, trail grades greater than 6%, and/or inadequate amounts of natural soil cements in the parent material. Some "refreshing" of trails material is required on a routine basis. Take a 5-kilogram (10-pound) sample of the proposed tread fill material to a materials testing laboratory, and have them perform a washed sieve analysis test to determine the percentage of minus No. 200 material. Since the minus No. 200 represents the amount of silt or clay, if the amount exceeds 20 percent, the material is not suitable. Typical cost for this test is between $35 and $50.

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Accessible Surface=Firm and Stable Accessible Surface=Firm and Stable

The surface is firm and stable if ruts are not left by:

► A bicycle with narrow tires.

► A 3-year-old in a folding stroller with small plastic wheels.

► Rotational Penetrometer

Two ways to measure if your surface is hard enough. Firmness refers to thepenetration of the surfacethat occurs when force isapplied, for example whenstepped on. Stability on theother hand, refers to thedisplacement of the surfacewhen a turning motion isapplied to the surface suchas the twisting of a foot. Inother words, firmness is avertical measure ofpenetration and stabilityinvolves how much surfacematerial shifts when rotatedpressure is applied

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ANSI/RESNA StandardsANSI/RESNA Standards

Very Firm/Very Firm/StableStable

Moderately Moderately Firm/ StableFirm/ Stable

Not Firm/Not Firm/StableStable

FirmnessFirmness 0.3 inch or 0.3 inch or less less

>0.3 >0.3 ££ <0.5 <0.5 inch inch

>.5 inch >.5 inch

StabilityStability 0.5 inch or 0.5 inch or less less

>0.5 >0.5 ££ <1.0 <1.0 inch inch

>1.0 inch >1.0 inch

American National Standards Institute, Rehabilitation Engineering and Assistive Technology Society of North American standards.

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Why crusher fines instead of Why crusher fines instead of concrete or asphalt?concrete or asphalt?

More natural appearance, easier/cheaper to maintain. Crusher fines trails provideaccessibility while maintaining the natural elements of your conservation area or park.

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Suitable Project for VolunteersSuitable Project for Volunteers

Trained volunteers can build and maintain crusher fines. The material doesn’t require much specialized equipment, except a compacter.

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““Greener Material”Greener Material”

Safer near wetlands, no oils like asphalt.Less energy intensive to process.Less heat reflectivity..

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More ComfortableMore Comfortable

Hiking or riding is always more comfortable on the joints versus asphalt or concrete!

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Cost EffectiveCost Effective

(Installed Costs/ Lin. Ft.- 8’ wide trail)

►Crusher fines surfacing-$4-$5/Lft.►Asphalt surfacing- $10/Lft.►Concrete- $14/Lft.

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LimitationsLimitations-- GradeGrade

Grade- apply crusher fines on trails no steeper than 6%

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RunoffRunoff

Every well constructed trail requires you to identify areas of runoff and prescribe construction methods to cross these streams.

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SoilsSoils-- HydricHydric, Expansive, Expansive

These soils need a stable base and/or a hardened surface.

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Softer SurfaceSofter Surface

Every few years you will have to add some material in spots where compaction, erosion takes place. However, this can be done with a minimum of equipment and skill level. In the long run this regular surface maintenance may still be less compared to the higher initial costs of pavement and its maintenance.

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Horses + Bikes = Increased Horses + Bikes = Increased MaintenanceMaintenance

Crusher fines being a “softer surface” doesn’t hold up as well with these additional users, if you want to have a firm and stable surface without much maintenance.

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Moisture/Compaction is CriticalMoisture/Compaction is Critical

Critical to getting this material to stay in place. You don’t want to get it too wet or too dry. Compact at least 4 passes.

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Case Study: Skyline RidgeCase Study: Skyline Ridge

The first wheelchair accessible trail I constructed in the Santa Cruz Mountains of Northern California. It is now 17 years old. I will be showing you pictures of recent condition to illustrate the effectiveness of crusher fines as a long term trail solution for accessible trails

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Roads, parking lots, and other trails are sources of surface water runoff, which must be picked up so it doesn’t affect your crusher fines trail.

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The trail begins at the parking area on the other side of the tunnel. There was a number of problems with drainage and erosion on the beginning. Afterwards, installed rolling grade dips minimized erosion.

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•Golden Fines were compacted in 3- to 4-inch lifts• Wet to moist, but not too wet, before it is compacted (not compacted when it is dry)• Compacted with a vibrating plate•Low lying wet areas had a base of ¾” drain rock encapsulated with geotextilefabric. This particular spot has a french drain on the left to carry subsurface water too.• Edges are “peeler cords” PT treated fir, and redwood edge to hold material and act as a barrier for safety.

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This trail section used a subbase of ¾ inch drain rock wrapped in filter fabric, “a burritto” for drainage. Then the crusher fines was placed on top betweenthese retainer logs

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This is the dam for Alpine pond. Crusher fines were placed on an excavated subgrade

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This section used recycled power poles as a safety barrier because of the drop off.

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The trail encircled the pond, starting at the parking lot going to the Nature Center it received lots of traffic. The material used was called “golden fines” (1/4” minus). Crusher Fines 1/4” minus, 4” minimum thickness.Specifications:Trail Width- 5 ft.Trail Grade- 5% or lessOut Slope- 3-5% or crownedPeeler cord or redwood edging¾ “ subbase at 4” thick with geotextiles on north side trail section.French drains at east side trail section.Redwood Bridges and/or culverts at crossings.

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This section of trail is part of the service road to the Nature Center. It allowed us to get a small tractor in and get the golden fines sited close to the project. The tractor used a box scraper to level the subgrade, then we used an old mining car that was modified with rubber tires to transport and dump the material, it was leveled and placed by hand. Timed compaction with a 1” rainfall.

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Trail Hardening with Road Trail Hardening with Road OylOyl

Soil Stabilization Products- Cold process flexible pine resin based material. Can be applied by hand, spray truck or mixed at the plant, transported like asphalt, and dumped into a paving machine. However, there is a timing issue with road oyl, as the material drys out it loses moisture, and “breaks” meaning the pine resin reaches a point where it needs to be compacted. Typically there is a color change from yelow/brown to brown when the moisture level is right for compaction.Process I used:•Place 55 gallon drums of road oyl every 100 feet along the side of the trail so the product is near sections where it would be applied.•With fire pumpers, spray water over the trail surface wetting crusher fines to help road oyl to spreadthrough the fines.•Pump product into a five gallon bucket. Pour into another bucket with numerous holes drilled into the bottom, and distribute over the surface at the rate of about 1 gallon per foot of trail.•Mix product with a rototiller•Landscape rake wet material for 3-5% outslope, about an inch above edging board.•Wait for color change from yellow/brown to brown.•Compact surface with plate compactor. Periodically spray with diesel to keep material from sticking to plate.•Let cure for two to three weeks, add a top coat, and cure for another week.

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Nature Pave Comparison to AsphaltNature Pave Comparison to Asphalt

Measured with a rotational penetrometer by Beneficial Designs for Soil Stabilization Products.

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GeowebGeoweb

The material cost can be $5/sq.ft, (crusher fines plus geoweb) plus labor. This puts it somewhere between asphalt and concrete. However, if your trail is in a remote location, it may be your best bet.

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ReviewReview

►►Best for hikers, wheelchairs, and mountain Best for hikers, wheelchairs, and mountain bikes.bikes.

►►Ensure trail surface level is crowned or Ensure trail surface level is crowned or outslopedoutsloped, 3, 3--5%.5%.

►►Add grade reversals for drainage.Add grade reversals for drainage.►►Keep grades around 5%.Keep grades around 5%.►►Don’t over rake.Don’t over rake.►►CompactionCompaction-- moisture level.moisture level.►►Get extra material for maintenance.Get extra material for maintenance.

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Maintenance/RepairsMaintenance/Repairs

►►Periodic surface repairs every couple of Periodic surface repairs every couple of years due to compaction, wear and tear.years due to compaction, wear and tear.

►►Inspect any drainage structures before or Inspect any drainage structures before or during rain events.during rain events.

►►Edges may need annual weed treatment.Edges may need annual weed treatment.►►Can add fines to material. Try 5Can add fines to material. Try 5--10% lime, 10% lime,

or cement to help bind aggregate.or cement to help bind aggregate.►►or add another hardening product. or add another hardening product.

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Soil Stabilizers On UniversallyAccessible Trails

USDA Forest Service Study in 2000.

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Larch HillLarch Hill

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Thank You !Thank You !

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ReferencesReferences

►►Forest Service Trail Accessibility Guidelines Forest Service Trail Accessibility Guidelines ►►Building Crusher Fines Trails, Building Crusher Fines Trails, BachenskyBachensky, ,

USFSUSFS►►Soil Stabilization Products WebsiteSoil Stabilization Products Website►►Photo CreditsPhoto Credits-- J.V. LittleJ.V. Little►►American TrailsAmerican Trails►►Trail Design and Management HandbookTrail Design and Management Handbook--

Troy Scott ParkerTroy Scott Parker