Used for the first time in South Africa on the rehabilitation of the R21 highway in Gauteng last month, specialised equipment manufacturer Astec’s RX-600ex cold planer is “poised to set new standards in road construction and rehabilitation”.

Astec materials and infrastructure solutions product sales manager Philip Saunders explains that cold planing is a cost-effective, repeatable and sustainable process, in which an asphalt surface is removed or milled up to provide an improved surface for repaving or resurfacing. It ensures smooth and uniform roadways.

In addition to motorway rehabilitation and milling, the RX-600ex’s applications include urban road projects. Its lighter weight and versatility ensure manoeuvrability in urban locations, while being suitable for lane profiling and maintenance.

The RX-600ex – which is powered by a 630 hp Cummins QSX 15 Tier 3 engine – is equipped with a 2 007-mm-wide QX1 asphalt milling drum with 16-mm tool spacing.

Additionally, the RX-600ex features a dust extraction system, hydraulically folding conveyor, Astec’s advanced computational engineering (ACE) Grade and Slope Automation with auto-cut entry, dual water spray bars and bolt-on track pads – all of which are standard on the machine.

Included on the cold planer is an Astec QX1 quick change cutter drum, an integrated dual operator platform that features simplified intuitive controls.

“The dust extraction system improves operator comfort and safety [by removing] dust and debris from the milling operation through a hydraulic fan at the primary conveyor,” explains Saunders, expanding on the cold planer’s features. 

He adds that the dust is ejected at the end of the secondary conveyor into the dump truck. “As the dust is ejected, the material exiting the secondary conveyor belt helps to channel the fine material into the dump truck.”

Further, the folding secondary conveyor, which is available on the Astec RX-600ex as “standard”, simplifies transport and loading. “A boost function, also offered as a standard feature on the machine, temporarily speeds up the conveyor should it become overloaded.”

He says that the cold planer’s Astec QX1 cutter drum improves access for bit and insert removal. The cutter drum’s notches in the seating face enable the use of a small wedge to remove inserts. The notches in the nose are for front bit removal with a fork tool. Further, the shorter base blocks provide “additional space at the end rings while the machine’s shorter shank allows for easier bit removal from the rear of the shank”.

Astec’s cold planers, such as the RX-600ex, have two independent spray bars to inject water in the cutting housing. The front spray bar is primarily for dust suppression while the rear spray bar cools the drum.

The ACE system enables the planer to automatically calibrate specific hydraulic parameters, ensuring that the machine consistently achieves the precise milling depth, while the grade and slope sensors maintain the prescribed parameters when in full operation.

The new graphic displays also allows the milling crew to easily select, calibrate and control the sensors with minimal time and effort, says Saunders.

Further, the ACE Auto-Cut Entry system automatically controls the drum's depth when initiating a cut, rather than requiring the operator to do so manually. It ensures that the drum connects with the pavement at the required depth and angle for the milling task.

Conveniently, the RX600-ex’s operator platform can be accessed from the right or left side, as the two control stations allow for machine operation from either side. The simplified controls also enhance ease of use.

“With multifunctional joysticks and accessible controls, operating the cold planer is clear and intuitive. The controls are designed to be operated with one hand to allow for truck signalling,” Saunders explains.

He adds that, when the track pads are ready to be replaced, the old ones can “simply” be unbolted and new ones bolted on, saving time and money.

This is because the bolts are not exposed to the surface, with the added benefit of there being no asphalt build-up. Saunders states that “traditional track pads [use] ‘through bolts’ which build up with asphalt and take longer to remove and replace”.

The RX-600ex is part of Astec’s expansive Rock to Road range, which includes equipment for every phase of road building –  from quarrying and crushing, to processing the aggregate, concrete production and road construction.

According to Saunders, Astec supplies more than 100 products to a global customer base in the aggregates, construction, infrastructure and mining sectors, and offers worldwide training, education, service and support.

The group’s operations are divided into two primary business segments. The first is Materials Solutions, which includes aggregate and other materials handling and processing solutions, including crushers, screens, apron feeders and rock breakers.

Meanwhile, Astec’s Infrastructure Solutions segment includes road building, asphalt and concrete plants, and thermal and storage solutions. High-performance, fuel-saving machines such as the Astec RX-600ex are ideally suited for infrastructure programmes in Africa.