To meet client specifications for the final product, new material can be added to the reclaimed asphalt. A patented Postheating, Drying and Mixing process ensures thorough heating of the reclaimed asphalt and added mix. Moisture, which is always present in deteriorated asphalt pavements, is removed. The mixture is then picked up by a slat conveyor and transferred to an onboard twin-shaft pug mill for final mixing before laydown and compaction. The resulting mix has the same controlled properties as hot asphalt mix produced in a stationery asphalt plant.
The Postheater/Dryer/Mixer is fitted with a hopper for the addition of admix. The quantity of admix, based on the mix design, is controlled by a metering device and monitored by the operator. The hopper can be easily removed from the machine for transportation.
The Postheater/Dryer/Mixer’s heating system is the same as in the Preheater and Preheater/Miller. It combines high-velocity forced hot air with low-level infrared heat. The system incorporates a diesel fuel burner, combustion air turbo blower, recirculating hot-air blower and a stainless-steel heating plenum. The burner heats a large amount of air in the heat-insulated, stainless steel combustion chamber. The hot air is forced into the heating tubes located in the insulated heating plenum. On the bottom of the heating tubes there are thousands of small holes through which the high-velocity hot air is blown onto the road surface. Since most of the oxygen from the fresh air is used for combustion, the hot air used for heating has low oxygen content, avoiding oxidation of asphalt binder.
Hot air is then vacuumed by the road surface by the circulating hot-air blower and blown back into the combustion chamber to be reheated. About 10% of the air is exhausted to make room for fresh air needed for combustion, which is supplied by the combustion air turbo blower. Four lifting and two tilting cylinders are used to adjust the heating plenum.
A fully computerized flame-management system, combined with an advanced fuel-control system, ensures the reliability of the combustion-chamber flame for safe and continuous operation. The operator can monitor and control the temperature of hot air from the operating station.
The combination of economic diesel fuel with the hot-air heating system provides a major advantage over other hot in-place recycling equipment: the AR2000 offers significant cost savings, a safer environment for operators, and conservation of energy and natural resources. Under normal operating conditions, the system is virtually emission-free.
Two Auger systems are incorporated into the Postheater/Dryer/Mixer. The front augers mix and spread the windrow under the heating plenum. The back augers mix and collect the asphalt into the slat conveyor.
The stirring devices under the heating tubes allow for the removal of moisture and thorough mixture of the added material with the reclaimed asphalt.
The slat conveyor transfers the hot reclaimed asphalt mix from the road to the onboard pug mill. Its speed can be adjusted to accommodate the working speed.
The onboard twin-shaft pug mill has a capacity of 300 tons per hour and is designed to thoroughly mix the recycled material for between 15-30 seconds.
The Postheater/Dryer/Mixer is self-propelled. Both the front and rear axles are equipped with hydraulic steering cylinders and can be steered independently. This will reduce the turning radius and ease the operation. The front axle is a tandem axle, and both axles can be individually steered. The train’s step-less speed control allows for easy adjustment of speed.
The hydraulic variable displacement pump is attached to a 246 kW CAT engine through a pump drive. Using hydraulics, the drive mode can be easily switched between operation and travel mode.
The machine is equipped with a dual brake system for safe and easy braking.
Electrical control and operation is designed for 24VDC. An onboard alternator charges heavy-duty 24V batteries.
Each AR2000 machine can be easily hitched to a tractor truck and transported at highway speeds between job sites.