Innovative technology for effectively incorporating RAP into asphalt paving mix.

Recycled asphalt pavement (RAP) is important for the asphalt business as it enhances both the sustainability and the profitability at asphalt mixing operations. Astec, Inc. has long been recognized as a leader in developing innovative technology for effectively incorporating RAP into asphalt paving mix.

The number one benefit of using RAP is cost. The aggregate itself hasn’t really aged. It has the same physical properties as it did the day it was originally crushed and used to make a road.

“The return on investment is high,” said Mike Varner, Astec Vice President Engineering. “If you look at the evaluation of recycle, that return comes from the value that is inherent in the materials that makes up RAP—the liquid that is in the RAP, the asphalt cement or the binder, and the rock.

Recycle is worth the material it’s replacing. Using recycled aggregate saves money that would’ve been spent on virgin aggregate and virgin binder. But it also can increase the longevity of pavements due to its stiffness, much like a polymer. Test results show this – especially if coupled with warm mix technologies.

The Double Barrel® XHR is a high RAP aggregate dryer with an external asphalt pavement mixer. This system uses V-flights and a drum VFD (variable frequency drive) to help facilitate producing many different types of mixes, while controlling the temperature. It cuts the added cost and the lost time of flight changes, because its wider veil increases its effectiveness by exposing more material to hot gases. The Double Barrel® XHR keeps operating costs down while making use of stockpiles of reclaimed asphalt pavement, running mix from 0 percent up to 70 percent RAP. It creates a high-quality mix with high RAP by employing two mixing technologies that have been around for a quarter of a century in the HMA (hot-mix asphalt) industry:

  • The outer mixing chamber on the dryer gently mixes recycle with dry hot aggregate maximizing heat and binder transfer between RAP, aggregate, and selected admixtures in a rarefied oxygen atmosphere.
  • The external mixer vigorously mixes virgin bitumen, as well as other admixtures.

The stainless-steel drum and combustion flighting withstand the higher temperatures associated with running high RAP.

Astec, Inc.
Innovation and customer service thrive in nearly equal parts at Astec, a global leader in the asphalt mixing industry. Building an asphalt plant from concept to completion requires experience, flexibility and trust. Astec is committed to bringing innovative products and solutions to the market by listening to the needs and wants of its customers. 

Says Andrew Pettingale, Managing Director at BG Europa, “Astec produces quality equipment which efficiently, cleanly and reliably produces high quality mix with high RAP contents. Its customer service in this industry is second to none and the attention to customers’ requirements is exemplary. Whilst competitors may imply, Astec provides written guarantees against performance.”

Along with technologically advanced equipment, Astec Inc. is committed to providing world-class sales, service, parts and technical support, delivering its customers the service they expect and demand in today's competitive environment.

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