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Astec’s Shuttle Buggy leads the way

With an ability to save time and costs while increasing pavement quality, construction company Fulton Hogan is just one of Astec’s many clients who are thrilled with the product.
With an ability to save time and costs while increasing pavement quality, construction company Fulton Hogan is just one of Astec’s many clients who are thrilled with the product.

The Shuttle Buggy has been a crucial piece of equipment to project sites since its introduction in Australian markets nearly 24 years ago.

Before the Shuttle Buggy, pavement failure due to asphalt segregation was a recurring problem. Delivery trucks would have to dump hot mix asphalt (HMA) directly into the paver causing a slew of problems.

Engineers realised that being able to re-mix the HMA before feeding it to the paver, was the key to increasing pavement quality. And hence, the earliest Shuttle Buggy was born.

As a material transfer vehicle (MTV), the Shuttle Buggy’s key purpose is to transport and remix HMA between the asphalt truck and paver.

The SB2000ex Shuttle Buggy is purpose built for the Australian market by infrastructure equipment and service supplier Astec. The SB2000ex distinguishes itself using advanced technology to remix the asphalt at an evenly maintained temperature.

With an ability to save time and costs while increasing pavement quality, construction company Fulton Hogan is just one of Astec’s many clients who are thrilled with the product.

“The SB2000ex comes into a world of its own,” says Alister Clarke, Surfacing Manager Infrastructure Services at Fulton Hogan. “It enhances the entire asphalt placement process by allowing non-segregated and uniformed heat transfer of the asphalt material which ultimately improves the rideability of the final road surface.”

“One of the reasons we decided to go with the SB2000ex is because during transport to site, the buggy is still below a legal weight without putting another dolly underneath,” says Clarke. “This comes with huge cost savings by not incurring additional float charges.”

Coupled with the buggy’s low weight and narrow wheelbase, the SB20000ex has a best in class steering radius allowing for sharp turns in tight situation and can be easily placed on transport trailers without restrictions.

Contactless Paving

A common issue before the introduction of shuttle buggies were bumps in the pavement, a direct result of truck to paver material transfer.

“The paver had to be virtually stopped to allow the truck to dump the HMA into it, “says Clarke.

This type of transfer also could cause spillages directly in front of the paver which was detrimental to the durability and a consistency of the road surface.

The SB2000ex facilitates continuous, nonstop paving by separating the truck unloading from the paving process.  Operators can either choose between using a dump hopper which is a large storage bin, or a windrow head which can pick up material to bring it the paver.

The dump hopper has been purposely sized for mass discharge from standard haul trucks, while its front hopper design allows trucks to unload fast.

“It can store up to 20 tons of HMA mix within the dump hopper, storage bin and conveyors, allowing dump trucks to unload as soon as they arrive on the job site, driving profits by eliminating truck delays and keeping the paver moving” says Clarke.

Blending of the Mix

Being able to evenly re-mix the product before adding it to the paver is half the battle to ensure pavement quality. The SB20000ex is able to achieve this continuous mixing through its triple pitch auger design.

A single auger design can pull materials away from the sides of any storage bin, however, for asphalt materials, this does not evenly re-mix the hot products. By introducing a triple pitch auger, the asphalt material can be pulled evenly across the length of the bin, ensuring uniform mixing of both larger and smaller particles and the product temperature.

he SB2000ex Shuttle Buggy is purpose built for the Australian market.
he SB2000ex Shuttle Buggy is purpose built for the Australian market.

The SB2000ex has been engineered for Australian conditions to provide the most consistent blending of HMA in terms of temperature and sizing, eliminating the common issues of thermal and material segregation that compromises the resulting asphalt mat.

The triple pitch augers provides uniform remixing across the entire width of the front hopper with the correctly sized and pitched augers remixing the contents of the storage bin.

This mixing action is done through a unique Astec remixing technology that equalises traction within the design that requires far less torque to drive the system resulting in a lower cost of ownership.

“The technology ensures large and small particles have been evenly remixed for a consistent continuously blending of the hot mix,” says Clarke.

“Our crew are able to monitor heat transfer on a regular basis through a handheld infrared camera to ensure the material temperature is uniform and consistence which is of the utmost importance, especially when it comes to cold weather and wind chill situations.”

A slat conveyor runs from the bottom of the hopper and feeds the discharge conveyor. The augers are the ideal size for remixing the material and carefully moving the material back to the paver while keeping the conveyor chain out of the mix again reducing the cost of ownership.

Features

Another innovation from Astec is the industry’s first FXS fume extraction system, installed as a standard equipment across all Astec Shuttle Buggies. This particular core feature directs the fumes and heat away from the machine which enhances vision and operator comfort.

The main operator’s platform has undergone major redesign work from previous models to provide unobstructed views around the machine from its elevated and outward sliding control station.

“This provides excellent line of sight, making for a safer and more efficient working environment. This unique design allows for clear all round operator vision, including seeing the people working around or near the machine,” says Clarke.

For even more “Smart Technology” to enhance operator confidence and greater efficiency, these new Shuttle Buggies can be fitted with an optional Auto Tracking Package.

This function automatically maintains and adapts to changes in paver speed and material flow, without the operators input.

“This aids in the uniform distance between the shuttle bugger and paver,” adds Clarke. “In my opinion, all forms of automation can help with key deliverables and are often sought after in road construction.”

The SB20000ex allows engine access by lifting the hood with a hydraulic mechanism while full hinged doors allow operators access to areas that are commonly needed for routine maintenance checks, from the radiator to the coolers and hydraulic pumps.

The C1 has a hydraulically powered lockout system eliminating the need of going under the machine to put the safety lock into position when servicing is required.

Multiple emergency stops are installed as a standard safety feature and all moving parts are enclosed to minimise the risk at pinch points and for increased safety around hydraulic drive components.

“Allowing easier access to machine components saves time and potential money when troubleshooting machine issues,” says Clarke.

With numerous innovative design features as standard on the SB2000ex and SB3000e translates to a smaller crew requirement and an increase in the overall end of job productivity, profit and customer satisfaction we believe.

Build Quality:

The materials to create the shuttle buggy are no less important than the role they play.

All conveyors on the SB-2000ex are outfitted with a durable offset side-wipe roller pin protector link chain for dependable in-service reliability. The auger flights are made of superior abrasion-resistant cast Ni-hard material, and the conveyor floors are covered with thick Chromium Carbide wear plate linings.

The floor of the paver loading conveyor C3 is insulated against heat loss with rails installed at the bottom of this conveyor that helps protect it from any damage that could be caused by the impacting with the paver.

“Due to all the “Class Leading” operational features the SB2000ex Shuttle Buggy offers us we’ve been able to provide our clients consistence rideability and greater durability than ever before,” says Clarke. “We already have two SB20000ex in our fleet and we are keen to see what other innovative products Astec will come up with.”

This article originally appeared in the July 2021 edition of Roads & Infrastructure Magazine. 


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