A lot has been happening in the road building segment since PMV Middle East last took a deep dive into the subject, with almost every major manufacturer announcing major project developments.
One player always vying to be at the front of the pack in the segment is the Wirtgen Group, which incorporates Vögele, Hamm, Kleemann and Benninghoven. Wirtgen is the first and only company to cover the entire road construction supply vertical with its own technologies: from crushing and screening, through mixing, paving and compaction to milling and finally recycling. Each of its five product brands specialises in its own field and focuses on its further development and enhancement.
In the last 12 months, Wirtgen has launched several cold-milling machines for road rehabilitation, including the W120Ri, which is the first in a generation of small mobile milling machines with rear loaders and equipped with poly-crystalline diamond cutters. Vögele has launched a number of Super Series pavers in tracked and wheel versions and Hamm introduced the pivot-steered DV+ series of tandem rollers, featuring its Easy Drive concept for simple, intuitive operation.
One development from Benninghoven is the GKL Silent, an electric asphalt mixer that eliminates all hydraulic components and thus noise, allowing it to dulcetly work through the night. The brand describes as a ‘quantum leap in mastic asphalt technology’ that meets present and future standards.
The omission of hydraulic components is complemented by the use of an extremely quiet power generator, which supplies the drive with electricity to direct and continuously drive the agitator.
With an acoustic pressure of 60 decibels at a distance of seven metres, the noise emission is equivalent to a television turned up to medium volume.
And the GKL Silent is not only quiet: accessories like a heated discharge door, central lubrication and an electric fill opening, make this mastic asphalt mixer a benchmark in value addition for end users.
Another milestone is the robust and fully computer-controlled operation of the GKL via touchscreen. Work data is also saved and can be accessed from the Webfleet Portal for subsequent reviewing.
The GKL Silent is available in a 3.3m³ to 10m³ range and can be installed on any heavy goods vehicle or flatbed trailer.
Benninghoven has stated: “In the future, it will no longer be permitted to transport asphalt with conventional mixers inside towns at night-time. The challenge was to build a mastic asphalt mixer with a diesel unit that does not keep on rattling.”
Stripping down
The combined strength of the Wirtgen Group is best demonstrated, however, when the products of its different divisions can be seen working together, and a great example in 2016 was in the renewing of asphalt pavement at Frankfurt Airport — a process that typically takes place every seven years.
The job in question was the re-paving of the four kilometre-long, 60m-wide central runway at Europe’s third-largest airport — including the processing of 20,000 tonnes of material in a timeframe of just 60 hours.
First up was the milling by four high-performance Wirtgen W250i, W210i and W2200 milling machines with two-metre and 2.2m milling widths and a total of 3,452hp. These machines milled 80,000m² of asphalt to a depth of five centimetres over a 2.6km-long, 31m-wide stretch of the runway. The milling job, including surface cleaning, was completed in 19 hours.
“The most critical points on major projects of this kind are usually the removal of the milled material and the water supply,” explained Klaus Kormann, site manager for the milling subcontractor GMS.
When it comes to water support, Wirtgen’s WiDrive machine management system monitors and controls not only the speed of the milling drum and conveyor as a function of feed rate and milling depth, but also the water system. It also automatically shuts off the water when milling stops.
In addition, the water pump pressure is automatically increased or decreased depending on engine load and milling speed. These functions significantly reduce water consumption, making the milling process much more efficient.
Once the milling machines completed their work, the asphalt paving was then carried out in two night-shifts, as at night the 35 trucks in operation could deliver the asphalt without being held up by the usual congestion around Frankfurt Airport.
Four Vögele MT 3000-2i high-performance feeders then fed 40,000m² of asphalt to four Vögele pavers: two Super 1800-3is, one Super 1900-3i and one Super 2100-2i.
The use of feeders was stipulated in the tender because surface accuracy is of critical importance on a runway. The feeders homogenised the mix using transverse, conical augers to ensure colder material from the edges or the transport trucks was mixed with warmer mass. Infrared heating then kept the feed conveyor at the right temperature to prevent mix from sticking.
These feeders can take on an entire 25 tonnes of load of mix from a truck in just 60 seconds. On this project, the four Wirtgen pave trains of feeders and pavers proceeded at a rate of about 500 tonnes an hour.
After two days and three nights, senior site manager Jörg Pigorsch was able to report the on-time completion of the asphalt paving work to his client.
He commented: “We saw the proof again of how reliable machines from the Wirtgen Group are. I always use machines from Wirtgen, Vögele and Hamm when time is a critical factor on a job.”
Family business
Another prominent player in the segment is sixth-generation family firm Ammann, which delivered this year on its status as an inventor with the prototype for an autonomous compactor.
While autonomous vacuum cleaners and lawn mowers have already entered the market it was Ammann that saw the autonomy of vibrating plates as a logical next step.
The first on the market, the autonomous vibratory plate compactor will be able to cover a jobsite without an operator, thereby providing a high compaction output at a reduced operating cost. The development is also good for operators, for whom exposure to vibration from hand-held equipment can have serious long-term health consequences, alongside the exposure to exhaust emissions.
A qualified operator is still essential to the success of the compaction project. The machines provide proper power, but the operator’s performance and attention to detail remain crucial to success.
The prototype is easy to use, with the operator setting the boundaries by remotely navigating the plate around a jobsite perimeter. Once the machine detects the closed border, it calculates a strategy and compacts the space strip by strip, supported by a GPS system, an electronic compass and collision detection. The plate delivers high-performance compaction while reducing labour, fuel costs and CO2 emissions.
However, when compared to vacuum cleaners and lawn mowers, an autonomous vibratory plate still raises considerable challenges, including the need to vary the compaction settings from site to site.
The advantages of such a solution are nevertheless obvious, including the significant cost savings for the contractor.
Milling around
Not one to be left behind, Caterpillar announced the distribution of its PM620 and PM622 cold planers — half-lane milling machines for the full-depth (up to 330mm) removal of asphalt and concrete paving — in the Middle East region in November.
Weighing in at roughly 33 tonnes for the PM620 and approximately 34 tonnes for the PM622, the machines are designed to be manoeuvrable and to productively achieve the full-depth removal in a single pass.
Both models are powered by the Cat C18 Acert engine — a turbocharged, six-cylinder diesel engine that provides 470kW (630hp) of gross power at either Tier 4 Final or Tier 3 emission standards. An automatic engine speed control then allows the engine to optimise output to match the load, reducing excessive fuel consumption and wear.
The PM620 is equipped with a 2010mm-wide rotor while the PM622 is equipped with a 2,235mm-wide rotor. Both are high -production and equipped with carbide-tipped cutting bits arranged in a chevron pattern for maximum breakout force.
Caterpillar can also provide diamond bits that last up to 80 times longer and provide even greater cutting performance.
The PM620 and PM622 can also be equipped with Cat Grade Control, a 2D-capable/3D-ready grade and slope system to maintain pre-set cutting depths.
Finally, the computerised monitoring system includes electronic control modules (ECM) that monitor system pressures and engine conditions and provide live self-diagnostics and fault reporting.
They require an engine oil service only every 500 hours, and a hydraulic oil service only every 3,000 hours, if oil sampling is not conducted, or up to 6,000 hours if scheduled oil sampling occurs.
