Earthbind® EBS-RA Cold-Mix Paving Success

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In the heart of the Columbia River Plateau lies Gilliam County, an area known for its beautiful rolling hills covered with picturesque golden wheat fields. Gilliam County is a rural and a sparsely populated dry land, wheat growing area located in north-central Oregon, east of the Cascade Mountains, approximately 150-miles east of Portland, Oregon.

Gilliam County Road Department maintains approximately 428-miles of road, of which more than 70% are unpaved. As expected, maintenance of their gravel roads proves to be a challenge.

A typical untreated Gilliam County unpaved road

According to Dewey Kennedy, Road Master of Gilliam County, as a result of their terrain and weather, their unpaved roads are a nightmare to maintain because of the steep grades and corners that consistently washboard under relatively heavy farm related traffic. Due to these issues, Dewey looked into the stabilization of the road base to hopefully mitigate these problems. Accordingly, the County experimented with several types of stabilizers all with limited success. However, about eight-years ago Dewey heard about a “local” product called Earthbind® Stabilizer and decided to test its efficacy as not only a base stabilizer but also as a dust control product. The results were good, Dewey states, “The Earthbind topical application worked amazingly well with both dust and wash-boarding. We graded the road sections and applied the diluted Earthbind to the roads and let it cure. The public thought the roads had been paved at first glance.”

At the same time, because of increasing traffic due to the booming windfarm industry, the County was also looking for an option for paving some of their more heavily traveled roads. Due to the county’s location, it was evident that hot mix paving was out of the question since the distance to the closest hot mix plant was too far. Thus, it appeared that cold mix paving was an alternative worth exploring even though the county’s past experience with cold mix proved to be unattractive due to cost. Dewey goes on to state, “We have our own rock crusher and our own pug mill. In the past we made old school cold mix for our projects. The cost of the cold mix oil had priced this process out of our budget, leaving us looking for other options.”

A Gilliam County road treated with Earthbind®

Gilliam County also has available a large supply of recycled asphalt grindings which they experimented with to upgrade some of their roads. They laid down the grindings both wet and dry using a grader, compacting, and covering with a chip seal. This application worked well but the downside was that the quality of the ride that left much to be desired.

Due to the objectionable results from their roads constructed with the asphalt millings, Dewey reached out to Troy Tindall, President of Blue Line Road Products, regarding one of their engineered products known as Earthbind® EBS-RA. The intent was to find an engineered asphalt emulsion that would optimize the effectiveness of the recycled asphalt grindings to be used for cold paving. This move turned out to be a good choice. Dewey stated, “We started running the grindings through our crusher into the pug mill adding 2½ to 3% Earthbind and laying them with a paver. This process worked so well we paved over 14 miles of gravel roads with the recycled asphalt Earthbind blend.”

Earthbind EBS-RA treated asphalt regrinds being laid down using a paver

With the success of Earthbind for cold-mix paving using the asphalt regrinds, Dewey then decided to experiment with the same emulsion and the same process on both clean and dirty “off-spec” virgin aggregate that the county crushes from local rock sources. Again, the experiment proved to be successful. “After the success with the recycled grindings, we produced a ½ – 10 clean rock with our crusher, ran this through the pug mill, adding 6% Earthbind and laid with a paver. The performance has been amazing and we have paved over 15 miles of gravel road with this method,” said Dewey.

A second lift of Earthbind® EBS-RA treated asphalt milling compacted

The more roads the Gilliam County Road Department paved using the Earthbind, the more efficient the process proved to be. “It took some trial and error and a patient roller operator to get the compaction process down, but the finished road looks as good as hot mix” said Dewey. In addition, Dewey considers the paving process using the Earthbind emulsion to be user friendly by adding, “Earthbind is very easy to work with either by hand, with a blade or paver. Cleanup at the end of the day is with a water truck for any equipment used. We run water and rock through the pug mill and put the rock back into the pile to be used the next day. The paver is just washed off and is ready to go.”

A close up of the Earthbind EBS-RA cold-paved asphalt grindings

In summary, the Gilliam County Road Department found a new cost-effective way to pave their roads, using their own equipment and crew, asphalt regrinds and their own virgin clean and “off-spec” aggregate, using a cold-mix paving and Earthbind Stabilizer product. Dewey concluded, “Performance has been amazing. We have some mix that has been down over eight years showing no wear.”

A Gilliam County road cold-paved with
Earthbind® EBS-RA and asphalt grindings

The cold-mix/Earthbind® process that the Gilliam County Road Department used to pave their roads is called “Ambient Mix Asphalt” process.

Earthbind® Stabilizer and Earthbind® EBS-RA are quality and environmentally-friendly biopolymer modified asphalt emulsions that is specifically engineered for dust control, base stabilization, and cold-mix paving applied at ambient temperature. Earthbind® is also ”self-tacking” which means that not only will Earthbind bond material together, seal the surface, add water resistance, control dust…it can also work as a “tack coat” to promote adhesion between a treated granular base and an asphalt surface treatment. All components of Earthbind® are considered free of hazardous solvents, non-flammable, non-corrosive to metal, and not considered to be harmful to aquatic and mammal life.

Earthbind® products are manufactured by EnviRoad® LLC, an ISO 9001:2015 certified company located in Portland, Oregon.