NEW MEXICO-CHIHUAHUA RURAL TASK FORCE Technical Workshop: Dust Control for Improved Particulate Matter Air Quality in Columbus-Palomas December 2, 2008

Low Cost Paving Alternatives Presented by Filiberto Castorena Technical Support Engineer New Mexico Department of Transportation

Dust Control

Conditions that Contribute to Blowing Dust Land cleared of all vegetation. Livestock grazing off vegetation. Non-maintained dirt roads.

Enforcement Authorities NMDOT has no enforcement outside of the Right-Of-Way. Many Counties and Municipalities have a Formal Plan on how to deal with airborne particulate matter.

Paved and Unpaved Roads Methods used by NMDOT Unpaved Road:  Place Base Course  Can’t chip seal unprimed base course  Bladed Depending Upon Weather Conditions  Can’t blade when too wet or too dry  Maintenance to V-Ditch  Very little maintenance needed  V-ditch cleaned while road is being bladed  Average Traffic Count  Traffic volume & roadway use will determine frequency of roadway maintenance Low Cost Paving Options:  Place Millings  Min. 3 inch up to 5 inch depending on road use  Chip Seal  $7,000 - $10,000 per lane mile  Cutler Repaving  $35,000 - $45,000 per lane mile  Brasier Method  $45,000 - $55,000 per lane mile-excludes base course cost

Maintaining Unpaved Roads Excerpt from Better Roads - November 2008 Issue Nearly 80% of the roads in the United States have traffic volumes of 400 vehicles or less per day, but they still need maintenance. Create and maintain roadside ditches to carry destructive water from unpaved road structures. Suppress dust with distributor truck applied dust palliatives (such as liquid calcium chloride) to protect surface and improve visibility. Crown of roadway must be maintained to direct water to ditches; FHWA’s Gravel Roads Manual (GRM) recommends the crown to be at or near 4 percent.

1.When a gravel road is maintained properly, it will serve low volume traffic well. Too-heavy haul loads will destroy even well-maintained roads, and poor maintenance will lead to fast failures, as shown in illustration #1. 2.Traffic at high speeds exacerbates washboarding, or corrugation. A good surface aggregate mix will have a higher percentage of plastic fines in the gradation, which in the presence of moisture will give the aggregate surface a “bound” characteristic. The bound surface will resist surface corrugation or washboarding. 3.This well-shaped gravel road shoulder slopes away from the road surface and drains water into the ditch. But it depends on a road with a good cross-section and crown in driving surface.

4.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 machine begins to “lope” or bounce, gouging depressions and making ridges in the road surface. 5.Clear ditches that become obstructed with eroded soil or debris. Major projects 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. 6.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 unpaved road surface. Some common dust palliatives, such as liquid calcium chloride (CaCl), absorb humidity from the ambient air, suppressing dust by keeping it relatively damp. These palliatives do more than just improve air quality; they keep your unpaved road literally from blowing away.

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

Chip Seal $7,000 - $10,000 per lane mile Chip sealing is the most economical method of road resurfacing. Chip sealing involves spraying an asphalt emulsion on the primed milling finish, then immediately spreading a layer of uniformly sized aggregate chips. The new surface is rolled to seat the aggregate. After a twenty-four hour curing period excess chips will be swept up.

Chip Seal

Cutler Repaving $35,000 - $45,000 per lane mile The Cutler process is a six step process: 1.heating the existing pavement 2.scarifying the heated, softened pavement to a one inch depth 3.applying a recycling agent to the scarified material to restore viscosity of the aged asphalt 4.mixing and laying the recycled material to form a leveling course 5.applying the virgin hot mix while the temperature of the recycled mix is still 225° F 6.final compaction

Cutler Repaving

Brasier Method $45,000 - $55,000 per lane mile-excludes base course cost This procedure utilizes a mobile mixing plant, distributor, paver and roller. Base course is mixed with oil and a “warm lay” is created. The warm lay is placed or "laid down" by the paving machine. New surface is compacted using the roller.

Brasier Method

Funding Sources Local Government Road Fund (LGRF) 75% State Funding / 25% Entity Match 75% State Funding / 25% Entity Match State Legislative Appropriations (LGAU) Severance Tax / General Appropriations Severance Tax / General Appropriations 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 the application process for this funding.

Any Questions?