June 7th, 2011

WMA JUNGLE

Preserve Infrastructure, by Catherine Higgins.

This post is fourth in a series about the Federal Highway Administration’s Every Day Counts Innovation Initiative.

FHWA’s Every Day Counts Innovation Initiative encourages the use of  Warm Mix Asphalt.

Granite Construction Company's Cottonwood Plant has been named to the Utah Department of Environmental Quality’s Clean Utah Program.

Using WMA can be a cost and energy saving approach with high quality results. UDOT allows the use of WMA as long as contractors provide a final product that meets the standards specified by UDOT engineers.

Hot Mix Asphalt and Warm Mix Asphalt have essentially the same basic components – asphalt binder and aggregate. Hot or cold, asphalt pavement comes in a variety of mix designs that vary the type, size and amount of asphalt binder and aggregate to determine the strength, thickness and durability depending on many variables, including underlying soil type, expected pavement life, climate and the traffic load carried by the road.

HMA uses heat to decrease the viscosity of the asphalt in order to be able to place and roll the pavement to the correct compaction. Adding Zeolite, surfactants or wax increases the ability of the asphalt to absorb water or makes the mix more workable so correct compaction can be achieved.

  • Adding water to hot asphalt during the mixing process causes mix to foam and achieve the viscosity that’s needed at lower temperatures to compact the product after installation. Granite construction has used WMA successfully in Utah for several years by using the water injection method to produce WMA.
  • “Zeolite is a mineral sponge used to transport water into the asphalt binder,” says Kevin VanFrank, UDOT’s Engineer for Asphalt Materials. “The foaming is more persistent and therefore the reduced viscosity lasts longer than simply adding water,” and lower compaction temperatures can be maintained for greater periods.
  • Waxes are thermosets “that lubricate and decrease viscosity of the mix at temperatures above their liquid phase transition but increase viscosity above the liquid phase transition,” explains VanFrank.
  • Surfactants (soap) are added to coat the aggregates to make the binder workable at lower temperatures without changing viscosity

WMA has several advantages. Less energy is expended to heat WMA; HMA is heated to 310 to 350 degrees Fahrenheit while the temperature range for WMA is as much as sixty degrees lower.

The compaction zone, or the temperature range at which asphalt can be successfully compacted, is wider than for HMA, giving workers more time to compact the asphalt once it’s placed.

WMA can be placed in the cooler months of spring or fall, which potentially lengthens the construction season. And, cooler asphalt has a milder odor, which can be good for road users and especially for workers.

WMA was successfully used on Wall Avenue in Ogden. During the project, WMA was placed side by side with HMA. “We couldn’t see any difference,” says Kevin VanFrank, UDOT’s Engineer for Asphalt Materials. The two asphalt mixes were tested extensively. “It all looks the same today,” says VanFrank.

 

Placing WMA on Wall Avenue in Ogden, Utah

See Granite’s Clean Utah Letter

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Responses to “WMA JUNGLE”

  1. Oh my gosh, what a great photo! I don’t think I’ve ever seen a project from that angle before (it’s usually speeding past the window).

  2. Learn more about Evotherm warm mix technology at http://www.evotherm.com and read case studies at http://www.behindthescreed.com. Evotherm WMA has been used in over 20 states on roads ranging from farm to market to busy interstate. It’s easy to use with proven performance!

  3. Information about ADVERA WMA Zeolite technology can be found at our website http://www.adverawma.com Our product is a proven technology that can be verified in laboratory mix before paving, with lower production temps than spray in water. Higher production fuel savings up to 30+% Lower emissions up to 70% total reduction. Higher RAP loading, longer haul times over 3 hours! Low price, HIGH Performance!

  4. WMA – it’s nice type of asphalt. WMA used in Moscow, Russia (my town) on MKAD. P.s. MKAD – is the most important ramp in Moscow.

    KIRILL VOEVODIN at March 23, 2012 9:00 pm
  5. But after two years of active use on the road track there. So you should think about choosing this type of asphalt.

    KIRILL VOEVODIN 2 at March 30, 2012 9:18 am
  6. Nice one! However, how would it really help to the environment? Is it environmental friendly?

  7. It is more friendly to the environment. Less energy is expended to heat the asphalt. And, 100 percent of asphalt can by recycled.

    Catherine Higgins at May 7, 2012 3:25 pm
  8. It would be good to do a followup to this article detailing the surface condtion of the road 12 months on.

  9. That is an amazing picture. Looking at that makes you appreciate the sheer scale of the plant.

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