Foamed asphalt is actually not asphalt at all. Asphalt is made in a very heat intensive process that is loud and gives off fumes and smoke. Green Mix- Foamed Asphalt is an environmentally friendly pavement made from 100% recycled aggregate.
Foamed Asphalt has been used for decades in Europe and Africa, and is now available in the U.S.. Green Mix is not an asphalt “wanna be.” Asphalt is far from a perfect material. The design life of most pavements is between 15- 20 years. Repair of existing pavements is a process that is almost never ending.
Many attempts have been made to create a recycled asphalt but very few have been successful. The difference with Green Mix is that by foaming the liquid asphalt, a much greater percentage of fine particle aggregate can be covered with bitumen. The result is highly stable material even though it is not continuously bound. Since it is not continuously bound, Green Mix foamed asphalt will not thermal crack like asphalt does (thermal cracking is caused by freeze/thaw cycles and is main source of failure in asphalt pavements).
The production of foamed asphalt starts with recycled pavement that is milled or crushed and is sized to a very specific gradation requirement. The process continues when a small amount of water is blended with hot liquid asphalt causing it to foam, not unlike a freshly poured soda…and making it well suited for mixing with the unheated bitumen aggregates. The recycled aggregate is then blended with foam and a small amount of Portland cement. The blending is computer controlled in a specialized plant designed specifically for producing foam asphalt. The process involves very little energy consumption and produces no greenhouse emissions.
Green Mix is not hot to the touch, so no personal protective gear is necessary. It is trucked to the jobsite and placed with traditional paving equipment so no special equipment is necessary. Green Mix stays workable for many hours making it versatile for a wide range of projects. On extremely hot days, workers appreciate not having to work with material that is over 250 degrees Fahrenheit.
After your pavement is fully constructed, it will look and perform like a pavement that is made with 100% traditional hot mix asphalt. The difference is that your pavement will be less expensive and will be much more environmentally friendly than a 100% hot mix pavement.
Many studies have been done to test the strength and stability of foamed asphalt. Some of these studies are contained on this website. Green Mix is the newest generation of foamed asphalt and our private study indicates it is equal to or better than other foam asphalts.
Why Now?
The original bitumen foaming process was a process that was patented by Mobil Oil in the 1950’s. The use of the technology then was restricted for many years by the patent protection. The patent rights were brought by a German company Wirtgen, and they sought to make equipment that would take advantage of the foamed process. Secondly, there has long been a lack of standardized mix design procedures meaning that more well documented and familiar products like hot mix have been preferred. Until very recently, no one would come forward to spend significant dollars to commission studies on foaming asphalt. Finally, more recently, the hyper escalation in the world price of petroleum has demanded closer attention to products that use much less petroleum than traditional products such as hot mix asphalt.
