NEW MEXICO-CHIHUAHUA NEW MEXICO-CHIHUAHUA RURAL TASK FORCERURAL TASK FORCE

Technical Workshop:Technical Workshop:Dust Control for Improved Dust Control for Improved Particulate Matter Air Quality in Particulate Matter Air Quality in Columbus-PalomasColumbus-Palomas

December 2, 2008December 2, 2008

Low Cost Paving Low Cost Paving AlternativesAlternatives

Presented by Filiberto CastorenaPresented by Filiberto Castorena

Technical Support EngineerTechnical Support Engineer

New Mexico Department of TransportationNew Mexico Department of Transportation

Dust ControlDust Control

Conditions that Contribute to Conditions that Contribute to Blowing Dust Blowing Dust

Land cleared of all vegetation.Land cleared of all vegetation.

Livestock grazing off vegetation.Livestock grazing off vegetation.

Non-maintained dirt roads.Non-maintained dirt roads.

Enforcement AuthoritiesEnforcement Authorities

NMDOT has no enforcement outside of NMDOT has no enforcement outside of the Right-Of-Way.the Right-Of-Way.

Many Counties and Municipalities have a Many Counties and Municipalities have a Formal Plan on how to deal with airborne Formal Plan on how to deal with airborne particulate matter. particulate matter.

Paved and Unpaved RoadsPaved and Unpaved RoadsMethods used by NMDOTMethods used by NMDOT

Unpaved Road:Unpaved Road: Place Base CoursePlace Base Course

Can’t chip seal unprimed base Can’t chip seal unprimed base coursecourse

Bladed Depending Upon Bladed Depending Upon Weather ConditionsWeather Conditions

Can’t blade when too wet or Can’t blade when too wet or too drytoo dry

Maintenance to V-DitchMaintenance to V-Ditch Very little maintenance Very little maintenance

neededneeded V-ditch cleaned while road is V-ditch cleaned while road is

being bladedbeing bladed Average Traffic CountAverage Traffic Count

Traffic volume & roadway use Traffic volume & roadway use will determine frequency of will determine frequency of roadway maintenance roadway maintenance

Low Cost Paving Options:Low Cost Paving Options: Place MillingsPlace Millings

Min. 3 inch up to 5 inch Min. 3 inch up to 5 inch depending on road usedepending on road use

Chip SealChip Seal $7,000 - $10,000 per lane mile$7,000 - $10,000 per lane mile

Cutler RepavingCutler Repaving $35,000 - $45,000 per lane $35,000 - $45,000 per lane

milemile Brasier MethodBrasier Method

$45,000 - $55,000 per lane $45,000 - $55,000 per lane mile-excludes base course mile-excludes base course costcost

Maintaining Unpaved RoadsMaintaining Unpaved RoadsExcerpt from Better Roads - November 2008 IssueExcerpt from Better Roads - November 2008 Issue

Nearly 80% of the roads in the Nearly 80% of the roads in the United States have traffic volumes United States have traffic volumes of 400 vehicles or less per day, but of 400 vehicles or less per day, but they still need maintenance.they still need maintenance.

Create and maintain roadside Create and maintain roadside ditches to carry destructive water ditches to carry destructive water from unpaved road structures.from unpaved road structures.

Suppress dust with distributor truck Suppress dust with distributor truck applied dust palliatives (such as applied dust palliatives (such as liquid calcium chloride) to protect liquid calcium chloride) to protect surface and improve visibility.surface and improve visibility.

Crown of roadway must be Crown of roadway must be maintained to direct water to maintained to direct water to ditches; FHWA’s Gravel Roads ditches; FHWA’s Gravel Roads Manual (GRM) recommends the Manual (GRM) recommends the crown to be at or near 4 percent.crown to be at or near 4 percent.

1.1. When a gravel road is maintained properly, it will serve low volume When a gravel road is maintained properly, it will serve low volume traffic well. Too-heavy haul loads will destroy even well-maintained traffic well. Too-heavy haul loads will destroy even well-maintained roads, and poor maintenance will lead to fast failures, as shown in roads, and poor maintenance will lead to fast failures, as shown in illustration #1.illustration #1.

2.2. Traffic at high speeds exacerbates washboarding, or corrugation. A Traffic at high speeds exacerbates washboarding, or corrugation. A good surface aggregate mix will have a higher percentage of plastic good surface aggregate mix will have a higher percentage of plastic fines in the gradation, which in the presence of moisture will give the fines in the gradation, which in the presence of moisture will give the aggregate surface a “bound” characteristic. The bound surface will aggregate surface a “bound” characteristic. The bound surface will resist surface corrugation or washboarding.resist surface corrugation or washboarding.

3.3. This well-shaped gravel road shoulder slopes away from the road This well-shaped gravel road shoulder slopes away from the road surface and drains water into the ditch. But it depends on a road surface and drains water into the ditch. But it depends on a road with a good cross-section and crown in driving surface. with a good cross-section and crown in driving surface.

4.4. Operating speed in blading operations must not be excessive. It’s almost Operating speed in blading operations must not be excessive. It’s almost impossible to do good work above a top speed of 3 to 5 mph, at which time the impossible to do good work above a top speed of 3 to 5 mph, at which time the machine begins to “lope” or bounce, gouging depressions and making ridges in machine begins to “lope” or bounce, gouging depressions and making ridges in the road surface.the road surface.

5.5. Clear ditches that become obstructed with eroded soil or debris. Major projects Clear ditches that become obstructed with eroded soil or debris. Major projects call for excavators and haul trucks, but maintenance operators can do great call for excavators and haul trucks, but maintenance operators can do great things with a simple motor grader, so long as conditions aren’t too wet.things with a simple motor grader, so long as conditions aren’t too wet.

6.6. A time-proven solution to dust from unpaved roads is use of a palliative (dust A time-proven solution to dust from unpaved roads is use of a palliative (dust suppressant), which forms a hygroscopic – or moisture absorptive – layer on an suppressant), which forms a hygroscopic – or moisture absorptive – layer on an unpaved road surface. Some common dust palliatives, such as liquid calcium unpaved road surface. Some common dust palliatives, such as liquid calcium chloride (CaCl), absorb humidity from the ambient air, suppressing dust by chloride (CaCl), absorb humidity from the ambient air, suppressing dust by keeping it relatively damp. These palliatives do more than just improve air keeping it relatively damp. These palliatives do more than just improve air quality; they keep your unpaved road literally from blowing away.quality; they keep your unpaved road literally from blowing away.

Low Cost Paving Options Low Cost Paving Options Place Millings - Can Ravel if Left UncoveredPlace Millings - Can Ravel if Left Uncovered

Chip Seal Chip Seal $7,000 - $10,000 per lane mile$7,000 - $10,000 per lane mile

Chip sealing is the most economical Chip sealing is the most economical method of road resurfacing.method of road resurfacing.

Chip sealing involves spraying an asphalt Chip sealing involves spraying an asphalt emulsion on the primed milling finish, then emulsion on the primed milling finish, then immediately spreading a layer of uniformly immediately spreading a layer of uniformly sized aggregate chips. The new surface is sized aggregate chips. The new surface is rolled to seat the aggregate. After a rolled to seat the aggregate. After a twenty-four hour curing period excess twenty-four hour curing period excess chips will be swept up. chips will be swept up.

Chip SealChip Seal

Cutler Repaving Cutler Repaving $35,000 - $45,000 per lane mile$35,000 - $45,000 per lane mile

The Cutler process is a six step process: The Cutler process is a six step process: 1.1. heating the existing pavement heating the existing pavement 2.2. scarifying the heated, softened pavement to a one inch depth scarifying the heated, softened pavement to a one inch depth 3.3. applying a recycling agent to the scarified material to restore applying a recycling agent to the scarified material to restore

viscosity of the aged asphalt viscosity of the aged asphalt 4.4. mixing and laying the recycled material to form a leveling course mixing and laying the recycled material to form a leveling course 5.5. applying the virgin hot mix while the temperature of the recycled mix applying the virgin hot mix while the temperature of the recycled mix

is still 225° F is still 225° F 6.6. final compaction final compaction

Cutler RepavingCutler Repaving

Brasier Method Brasier Method $45,000 - $55,000 per lane mile-excludes base course cost$45,000 - $55,000 per lane mile-excludes base course cost

This procedure utilizes a mobile mixing plant, This procedure utilizes a mobile mixing plant, distributor, paver and roller.distributor, paver and roller.

Base course is mixed with oil and a “warm lay” is Base course is mixed with oil and a “warm lay” is created.created.

The warm lay is placed or "laid down" by the The warm lay is placed or "laid down" by the paving machine.paving machine.

New surface is compacted using the roller. New surface is compacted using the roller.

Brasier MethodBrasier Method

Funding SourcesFunding Sources

Local Government Road Fund (LGRF)Local Government Road Fund (LGRF) 75% State Funding / 25% Entity Match75% State Funding / 25% Entity Match

State Legislative Appropriations (LGAU)State Legislative Appropriations (LGAU) Severance Tax / General AppropriationsSeverance Tax / General Appropriations

Federally Funded-Surface Transportation Program (STP)Federally Funded-Surface Transportation Program (STP) TPU – Large Urban Areas (pop. 200,000 +)TPU – Large Urban Areas (pop. 200,000 +) TPO – Small Urban Areas (pop. 5,000 – 200,000)TPO – Small Urban Areas (pop. 5,000 – 200,000) TPM – Rural Areas (pop. Under 5,000)TPM – Rural Areas (pop. Under 5,000)

Contact your RPO / MPO or COG for assistance with Contact your RPO / MPO or COG for assistance with the application process for this funding.the application process for this funding.

Any Questions?Any Questions?