Will polymer replace asphalt?
The asphalt on our roads is perceived by many like the gas in our tanks. We simply consider it indispensable. The truth is that asphalt can be replaced, as the booming Concrete Paving industry has proven to us already. This is not a finger pointing article, far be it from me. I would like nothing more than to see all asphalt professionals get more involved with alternative technologies, since they already have much of the equipment necessary, and it helps them build and repair more road, more efficiently and more competitively.
Environmental issues of asphalt:
Asphalt makes an excellent road surface, there is no denying it. However, it is toxic not only to the workers absorbing the fumes, but also to the ground, water and generally the environment it sips into.
Center for Disease Control (CDC) - Research on Asphalt Toxicity
National Park Service, Colorado State University - Environmental Contaminants, Asphalt
Virginia Dept of Transportation - Leaching & Toxicity of Recycled Asphalt Pavement to Aquatic Organisms
Over the last two decades we have had summers so hot, that the temperature retained by asphalt is becoming newsworthy problem in larger metropolitan areas worldwide, especially with the elderly population.
Why do we still use asphalt after 40 years?
For the same reason we still pump gas in cars. We often assume that science and technology will secure the continuous improvement of productivity and quality, all at decreasing expense. While noble in theory, current business practices demonstrate that we rarely maintain this never-ending path of improvements, and even resist fundamental breakthroughs due to carefully protected investments and comfortable profit margins.
What is asphalt? (wiseGeek.com)
Asphalt is a thick brownish or black substance derived from the same crude oil which produces kerosene, gasoline and vinyl. It is literally scraped from the bottom of the barrel after all other petroleum-based products have been refined or processed. The tar from the crude oil is usually mixed with sand or gravel (often called aggregate) to form the finished product we call asphalt. The black tar forms a strong adhesive bond with the aggregate, which makes it durable. When used in road construction, asphalt is usually poured over a bed of heavier aggregate in a heated state, then pressed into place by an extremely heavy steam roller. Asphalt does have some drawbacks as a construction material, however. The sulphur fumes released during the heating process can be hazardous to workers and very unpleasant for passers-by. Traffic and constant exposure to the elements can cause asphalt to wear out faster than anticipated. Because the ground beneath the asphalt can repeatedly freeze and thaw, asphalt roads are susceptible to cracks and pothole formation.
Concrete as an alternative
Concrete has always been a great alternative to asphalt. However, it comes with a drawback. If you don't have top notch equipment and engineering from the first layer of base to the last day of work, any missed step or corner cut will inevitably transform into a costly tragedy of proportions unimagined just a few short years later. Concrete as an alternative is cleaner but costs are about the same. Do concrete properly, and it probably costs much more than asphalt. You do get a long lasting, durable road in return.
Polymer as an alternative
Polymer technology (advances in chemistry which allow us to make long strings of molecules) has gradually entered the paving industry, as it has into many other areas. The first to cross into the paving industry were companies which provided dispersible polymer for dust control.
How does polymer address the strength problem?
A good polymer will bond just like asphalt. Just like with asphalt sourcing for good aggregate will make your road as strong as the rock you are bonding with the polymer. Some projects use crushed rock to gain incredible bond and surface strength.
Elasticity
Polymer molecules are long, allowing a great level of elasticity without compromising road strength. Polymer will remain elastic for many, many years after asphalt starts to crack.
Heat Island Effect
The dark color of asphalt is due to the fact that is is 80 ACRYLIC.
How can I tell what I'm looking at?
An easy way to determine polymer quality and type is by reviewing the respective product's MSDS. An MSDS that shows a wide range of pH will be inconsistent, will likely be a vinyl copolymer blend, and if the pH is below 7 it will likely be all vinyl. An MSDS that has a range for percent solids will be inconsistent, and so will be your road.
When long-term stabilization is the goal, it is important to check the MSDSs of each potential product to ensure that one is using a product that can stand up to the required task for the time frame necessary with the least possibility of requiring reapplication.
Where to buy the correct polymer for road paving applications?
PolymerPaving.com markets accessory products that enhance the already good characteristics of the DirtGlue polymer exponentially. These accessory products allow DGp to cure faster, to be applied at lower temperatures, to tolerate high plasticity soils such a clays and silts much better, and to enhance overall bond strength. This is the only polymer soil stabilization company that has this new and superior technology.
Additional details are available from
projects@polymerpaving.com