Potawot Paths
Potawot Health Village is located on 40 acres of land in Arcata, CA. Approximately two miles of paths have been constructed on their land in order for the community to enjoy the conservation land that surrounds their main facility. Instead of applying conventional asphalt to the land, a natural alternative, pine resin pavement, was used to create the pathways.
Material Description: Pine Resin Pavement
Pine Resin pavement is a combination of regular aggregate, or crushed rock, sealed together with pine rosin and pitch from pine trees (Product Review, 1999). This natural alternative to asphalt isn’t mixed and poured hot as regular asphalt is, but instead mixed together through a cold process. Water and the pine emulsion are mixed together with water and then laid out where it is needed. The mixture is then compacted and left to set. Instead of the product setting by cooling, it sets through evaporation of water leaving the mixture. Much of the energy required to lay normal asphalt is avoided because the mixture does not have to be heated up, saving precious fossil fuel resources. Also, because the adhesive material is made of tree resin rather than normal asphalt, there pavement doesn’t contain any VOC’s of PAHs. The final product is similar in appearance to asphalt in texture and thickness but can vary in color. The pine resin transparent and takes the color of the aggregate.
Durability
The strength of pine resin pavement varies due to the quality of application, site location and actual pine resin product used. NaturalPave XL, a pine resin distributor put it's product to the Marshall Stability Test. This test heats up the pavement to 140 F and then observes how the pavement responds to heavy weight applied. NaturalPAVE XL withstanded "8,000 to 18,000 pounds" (NaturalPAVE XL, 2008). The document also stated that the typical Marshall Stability results for conventional asphalt are generally 4,000 to 6,000 pounds.
Other studies have claimed that resin pavement has three times the compressive strength then that of asphalt and that resin pavement is 'highly water-resistant". (Product Review, 1999)
As impressive as these finding are, the possibility for large scale use seem to be limited to low traffic areas as "cold mix is certainly not for roads subjected to medium to heavy traffic." (Dooley, 2008)
Cost
Comparison to Conventional Asphalt
| Advantages | Disadvantages |
|---|---|
| - High solar reflectivity: it reflects more sunlight so the pavement absorbs less heat. | - Limited to use to low traffic areas |
| - No Toxic Chemicals are in the pavement itself, or are emitted during application. | - High Cost |
| - Materials are natural and renewable | Labor Intensive |
| - Application is not energy intensive | Certain outdoor temperatures are needed for proper finishing |
| Salon | 4.56m x 6.6m |
| Total project | 9.75m x 4.56m x 2.7m |
References
- Dooley, Erin E. “New Default for Asphalt?” Environmental Health Perspectives vol.116, no 9, pg 379, 2008.
- “Paving Without Asphalt or Concrete”Product Review: Environmental Building News. Nov. 1, 1999.
- NaturalPAVE® XL “Technical Bulletin-Pavement Preformance Testing.” Soil Stabilization Products Company, Inc.
- NaturalPAVE® XL “An aesthetic, environmentally friendly alternatice to asphalt”. Soil Stabilization Products Company, Inc.