Mojave National Preserve, National Park Service, Cima, California

Point of Contact David Burdette

Project Summarypicture2

Figure 1: Zzyzx Road from Interstate to Zzyzx

Mojave National Preserve (Mojave NP) diverted fourteen thousand (14,000) tons of asphalt cuttings from a landfill and reused them to pave 4.1 miles of Zzyzx Road during July and August 2008.  There was no cost for asphalt cuttings nor for the delivery of cuttings, which resulted in substantial savings to the National Park Service (NPS).  The 14,000 tons of asphalt cuttings were recycled from a paving project on a 17-mile section of Interstate 15 (I-15) near Zzyzx Road.  Mojave NP’s use of the cuttings eliminated the need to transport them to a distant landfill and avoided the production of green house gases during transportation to landfill.  The paving project improved the road surface from poor to excellent, plus reduced the generation of dust and particulate matter that affects visitors and wildlife. 

Project Description

Zzyzx Road is approximately 4.5 miles long and is located in the northwest corner of Mojave NP.  The road runs from I-15 to Zzyzx, where there is picnic area operated by the NPS and the Desert Studies Center.  The Desert Studies Center occupies a former resort located on the shores of Soda Lake that is now a non-profit education and research center operated by the University of California at Fullerton.

The asphalt cuttings reused in this project were generated during a resurfacing project on I-15 completed under a contract with the California Department of Transportation (CalTrans).  Before the contractor could apply the new asphalt surface, the top layer of the old asphalt had to be removed with large grinders.  Normally, the old cuttings would be discarded in a landfill.  CalTrans encourages their contractors to recycle the used asphalt cuttings rather than add useable material to the State’s landfills.  Since the 17-mile section of the Interstate that was scheduled to be resurfaced was close to Mojave NP the subcontractor (Boone Trucking) who won the bid for the transportation and disposal of the asphalt cuttings contacted Mojave NP.  Boone Trucking

Figure 2: Zzyzx Road after being paved with recycled asphalt cuttingsNorth end of Rd

contacted Steve Carlson, Mojave NP’s Chief of Maintenance, during the spring of 2008 to inquire if Mojave NP had any use for the cuttings.  Mr. Carlson was interested in the cuttings and came up with a plan to use the cuttings to pave Zzyzx Road, but he wasn’t sure if he could make it work.  Mojave NP would need to find additional funds to complete an unplanned paving project and to develop a contract that was flexible enough to perform the work on Boone Trucking’s schedule.  Mr.

Carlson contacted the Facilities Management Section of the Pacific West Regional (PWR) Office of the NPS for help.  PWR helped Mojave NP secure the needed funds by adjusting and modifying some other projects in the fiscal year 2008 budget.  PWR moved Mojave NP up in the ranking of projects, so that the funds originally scheduled for repairing the dirt road in out years could be spent in 2008 to pave the road.  Paving the road was a more permanent option as opposed to grading and adding gravel to the road.  Even though the initial cost to pave the road with recycled asphalt was more than the cost to grade and gravel the road, a permanent fix would reduce yearly maintenance so it made fiscal sense. 

Figure 3: Section of road left unpaved to preserve natural springs

Seeps in roadThere were challenges for Boone Trucking as well.  They wanted to make a profit and properly dispose of the old asphalt cuttings.  Boone would deliver the cuttings to Mojave NP at no costs, but the cuttings had to be used within a short period of time after delivery in order to prevent the cuttings from consolidating into large mounds of asphalt in the extreme desert heat.  Therefore, Boone was relying on Mojave NP to set up a contract with a flexible schedule.  If Mojave NP agreed to accept the cuttings, then Boone Trucking would save money by avoiding the disposal costs and the additional expenses of transporting the cuttings to a distant landfill.  Looming over all of these operations was the certainty that the environment would suffer from the greenhouse gases that would generated by numerous large trucks that would be required to transport 14,000 tons of asphalt cuttings to a distant landfill. 

PWR sent $325,000 to Mojave NP as a cyclic maintenance project to repair an existing road.  The contract was written to include a flexible schedule with donated material that had a short shelf life.  Mojave NP’s contracting officer Jim Read negotiated with Brittan Construction, a small disadvantaged business that agreed to be ready to work on road when the cuttings were delivered.  Mojave NP awarded the contract to Brittan Construction.

Figure 4: Desert Bighor Sheep on ZzyzxRoad Sheep

In order to minimize the inconvenience to the staff of the Desert Studies Center and the public, Mojave NP mandated that the work be performed during the night.  Park maintenance staff and Brittan Construction worked through the night so that the road could stay open during daylight hours for the public.  Brittan Construction started work on July 14th.  They prepared the gravel road for the paving by grading and compacting it.  Boone Trucking began delivering the asphalt cuttings on July 20th and continued each night for the following 11 nights.  Brittan mixed the cuttings with a non-corrosive polymer binding agent (Soil-Sement) that is advertised as environmentally safe.  Brittan Construction applied the asphalt/ Soil-Sement mixture to the road under the oversight of Mojave NP's Maintenance Foreman, Allan Hurd in order to create a hard packed surface that will last for many years.  The work was completed on August 1, 2008.  The project required a considerable amount of coordination between the trucking company, Mojave NP, the PWR Office, Britten Construction and the visitors and staff at the Desert Studies Center. 

The outcome of this project provides clear benefits for Mojave NP and its many users.  Before the paving project, Zzyzx Road was a dusty dirt road that was partly covered with gravel.  The paving of the road has greatly reduced the amount of particulate matter and nuisance dust that was generated when vehicles drove over the dirt road.  The newly paved road has improved the access route to the NPS’s Soda Lake picnic area and the Desert Studies Center.  Even though vehicle counts or other data for visitors use has not been collected by the NPS for Zzyzx Road, the Desert Studies Center has been collecting data on “User Days” or the days that an official guest of the center is attending an event, class, or performing research at the center.  During the last 5 years, the Center has hosted between 1,975 and 2,382 official guests each year.  User days have ranged from 6,035 to 6,489 days each year.  The director of the Desert Studies Center has estimated that a visitor might travel Zzyzx Road several times each day while in residence at the center.

For environmental reasons, not all of Zzyzx Road was paved.  A short section of the road was left unpaved to protect a local herd of the Desert Bighorn Sheep.  The unpaved section contains natural springs or seeps that are used by the bighorn sheep.  The bighorn sheep also use this section road as a migration corridor between Soda Mountains and Soda Lake so this part of the road was not paved in order to reduce the speeds of passing vehicles.  This section of the road also has sharp turns with blind curves that could conceal the presence of animals. 

Some of the benefits of this project include:

  • Eliminated the need to transport the asphalt cuttings to a distant landfill
    • Avoided production of greenhouse gases during transportation to landfill
    • Diverted 14,000 tons of material from landfill
  • Conserved diminishing resources of aggregates and petroleum products
  • Substantial cost savings to pave road with recycled asphalt cuttings
  • It cost $324,205 to pave road with recycled asphalt and cementing agent
  • Estimates to pave the dirt road range from $350,000 to $500,000 per mile ($1.44 to $2.05 million for the project)
  • Asphalt cuttings that were used as road material were donated
  • No cost to government for delivery of the asphalt cuttings
  • Improved the road surface from poor to excellent
  • Reduced dust and particulate matter for visitors and wildlife

Figure 5: Transition from paved to short unpaved section

S pavement End sign The Zzyzx Road paving project is a success in flexible team work, working smarter, reusing materials that would have gone to a landfill, and saving valuable taxpayer funds in this time of fiscal austerity.  This project reduced the impact on the environment by recycling the asphalt cuttings, by conserving the energy that would have been expended by transporting the asphalt cuttings to a distant landfill as opposed to transporting the asphalt cuttings to Zzyzx Road, and by educating the visiting public about recycling.


U.S. Department of the Interior

Greening of the Interior