Warm Mix Systems

Aste V-Flights for asphalt drum mixers

Double Barrel® Green System

For use with Astec Double Barrel® and Double RAP® drum installations.

Green Pac™ System

For use with Astec Double RAP® drums and all brands of drum mix coaters, parallel flow drums, batch towers and non-Astec equipment.

Water Reservoir

A skid-mounted corrosion-free water reservoir is included with warm mix system packages. An optional cold weather package is available to prevent damage to components when temperatures drop below freezing.

Warm Mix Systems for Continuous Mix and Batch Plants

The benefits of warm mix asphalt such as reduced energy consumption, lowered emissions, and elimination of visible smoke are well-known in the asphalt paving industry. Warm mix technology allows mix to be prepared and placed at lower temperatures, typically 50°F to 100°F lower than conventional hot mix. To achieve this, the viscosity of the asphalt cement (AC) must remain low at the reduced temperatures. Maintaining a low viscosity at lower temperatures allows mix to flow freely through storage, transfer and placement equipment and is more easily worked by hand.

Unfortunately, many technologies for warm mix production rely on additives, special asphalt cement, special procedures and/or special AC delivery systems to achieve low viscosities at low temperatures. The additives are expensive and add significant cost per ton of mix. Astec warm mix systems eliminate the need for expensive additives and special asphalt cement by mixing a small amount of water into the AC to create microscopic bubbles. These small bubbles act to reduce the viscosity of the AC coating on the rock allowing the mix to be handled and worked at lower temperatures.

Water is delivered to the system using a positive displacement piston pump capable of accurately metering water into the system. Using feedback controls, pump speed is modulated to maintain the appropriate flow of water based upon the flow of AC. PLC controls provide for smooth and consistent water flow as production rates increase or decrease.

Water is injected into the liquid AC through a series of all stainless steel injectors located above corresponding foaming chambers. AC flows through the foaming chambers where water and AC are thoroughly mixed to produce mechanically foamed AC.

A skid-mounted corrosion-free water reservoir is provided with an automatic filling valve. If supply water is lost, a low-water alarm alerts plant personnel so the problem may be resolved quickly without wasting mix.

Astec can retrofit warm mix systems to continuous mix and batch plants from any manufacturer, bringing the benefits of the Astec warm mix system to all asphalt pavement plant configurations.

AC MANIFOLD - Field-proven and highly reliable.

Easily work the low-viscosity mix by hand.
Side-by-side comparison: left traditional mix, right mix produced with the Double Barrel Green System.
Roadtec RP-190 paver laying warm mix from an Astec warm mix system. Notice no visible smoke emissions.