Asphalt paving design advances

A diverse array of advanced paver designs is now being offered in the asphalt paving sector – Mike Woof reports

With the World of Asphalt and 242 INTERMAT 2012 events having both taken place in recent months, a series of innovations have been introduced for the asphalt paving market. Developments have come to market that widen the array of both US and European asphalt paving systems and all the major manufacturers have developed new pavers and materials feeders to meet the latest emissions requirements.

Demand is growing worldwide for asphalt paving machines also, with manufacturers gearing up to meet customer needs.

From Ammann comes the AFW350 and AFT350 medium-sized asphalt pavers, which are said to offer good manoeuvrability in confined areas. These hydrostatically driven machines offer a paving width from 1.8–3.5metres and the output potential of up to 230tonnes/hour. The machines have been reconfigured to work efficiently with 6791 Ammann’s compaction machines and a wide range of optional equipment is available to improve paver performance. These include a vibratory screed or a tamping/vibratory screed that can be heated with either gas or electricity, and automatic lighting and temperature control functions.

172 Bomag’s BF 800 is a 20tonne machine that shares design features with the smaller BF 300 and BF 600 models. The BF 800 offers paving widths of 2.5–10m and is designed for medium to large-scale construction projects on highways and major roads, although it also benefits from a compact design that allows it to work in urban applications where space is at a premium.

Available in wheeled or tracked models, the BOMAG BF 800 is powered by a 139kW, six-cylinder 201 Deutz engine featuring low noise and emissions. An ECOMODE machine management system is said to further reduce fuel consumption and emissions.

The screeds feature electric heating as standard, with heating elements cast in an aluminium block for durability and reliability. Optimised heat transfer is said to ensure
good heat distribution as well as fast heating-up times.
For the maximum screed extension of 1m, mechanical attachments are used, fitted with quick fit sliding couplings to reduce set-up times. The screeds allow paving thicknesses of up to 300mm and crown adjustments of -2.5% to +4.5%. Meanwhile, high pre-compaction and surface finish performance is claimed for both the tamper and vibration units.

178 Caterpillar is looking to raise its profile, and in the EAME paving segments in particular. Josh Meyer is region manager for Caterpillar’s paving products in EAME territories and said that the firm expects to see considerable growth in sales. Meyer said: “The paving business is back in the mode of expansion. Even in Europe we’re starting to see growth in spending in infrastructure and growth in the paving business.”

The company has had sales success in the Middle East and North Africa, for example, and is also pushing hard with its paving products in Europe. Caterpillar is looking to increase its market share and is introducing 20 new paving and compaction machines. Meyer said, “We as Cat have been investing heavily in our product lines.”

“In Africa, Latin America and Asia we’re seeing enormous growth in new road development. In North America and Europe we’re seeing more investment in road maintenance and road rehabilitation.”
Caterpillar is offering an improved range of pavers also, with the diminutive AP255E being the firm’s biggest move in the sector as it has been designed specifically for use by European customers. The paver is intended to operate in limited spaces, due to its compact design and exceptional manoeuvrability. The AP255E is powered by a Cat C2.2 engine delivering 34kW, weighs 4.5tonnes and has a standard paving width of 1.4–2.6m. The firm’s paving controls are also offered with this machine. Its AS3143 electric screed is powered by an onboard generator with independent temperature control in all four sections. Three heating elements for each screed section ensure uniform heating over the entire screed plate.

The AP555E also offers the AS4251C tamper bar screed with two double-width hydraulically driven extenders for excellent stability on wide-width paving applications. Fitted with extensions, the AS4252C screed can pave widths up to 7m on the wheeled AP500E and up to 8m when used with the tracked AP555E. The standard, extendable paving
range is 2.5–5m.

Key improvements for the mid-sized pavers are more screed options and improved fumes extraction systems. Wheeled and tracked models are available and the AP500E and AP555E pavers are designed for global use in a wide array of jobsite applications. The machines are available with both vibratory screeds and tamper bar screeds with vibration, suiting them to both US and European applications, while a notable benefit is the sophisticated fumes extraction system.

Independent research recently concluded that as much as 92% of fumes are re-directed from Cat pavers by a new system that collects fumes from the auger chamber as well as the conveyor tunnel and routes them through the exhaust stack. In addition, the front-mounted cooling fan blows fumes away from the hopper and the paver operator. The AP555E is fitted with the Mobil-Trac undercarriage, which is said to offer good mobility on the jobsite. The AP500E can be used on hard surfaces or soft base materials and features non-directional, radial drive tyres that provide a large ground contact area for good flotation, stability and tractive effort. Both the AP500E and AP555E feature a Cat C4.4 engine that provides 106kW.

Dual swing-out operator stations, tilting consoles and a low-profile design are said to provide good forward visibility. The operator can extend the station beyond the machine frame when matching joints or monitoring the auger chamber. The AP500E is available with three screeds: The AS2252C, the AS3251C – and the tamper bar screed, the AS4252C. The AS2252C vibratory screed features narrow front-mounted extenders. The extenders have 229mm-wide screed plates, enabling it to work close to obstacles and making it a perfect fit for urban applications by reducing the need for handwork when changing paving widths. The AS3251C vibratory screed features hydraulically driven, rear-mounted extenders.
The AP1000E and AP1055E pavers replace the earlier D-Series' machines. The AP1000E is a wheeled model while the AP1055E is the tracked version of the same basic machine. Productivity is provided in part through the heavy-duty screed designs offered, with customers able to choose between the AS2302C, AS3301C, AS4251C and AS4252C. The AS2302C and AS3301C feature vibratory screed plates, while the AS4251C and AS4252C come equipped with tamper bars and vibratory screed plates. As with the AP500E and AP555E, these models are equipped with the fumes extraction system. Like the smaller AP555E, the AP1055E is offered with the Mobil-Trac undercarriage, while the AP1000E also has non-directional radial drive tyres like the AP500E.

In markets that require Tier 4 Interim and Stage IIIB standards, the AP1000E and AP1055E will feature a Cat C7.1 engine with ACERT Technology, while machines that are only required to meet Tier 3 or Stage IIIA emission standards come equipped with the Cat C6.6 engine with ACERT Technology. Both engines deliver 168kW. Cat pavers can be equipped with the Cat Grade and Slope control system, which is factory-integrated and removes irregularities from the surface while controlling mat thickness for increased production, lower operating costs, and higher profitability.

206 Dynapac continues to innovate with its paver range, following from previous developments in 2010 and 2011. The firm has said that it is now improving the operator´s environment and transport sizes, as well as gearing up to meet future exhaust emission regulations. The firm introduced six new tracked asphalt pavers with paving widths of 2–14m. Of these, the four sophisticated PLC-controlled pavers - SD2500 C, SD2500 CS, 2D2550 C and SD2550 CS - are being offered with exhaust emission technology meeting the Tier 4 interim/Stage IIIB regulations. The SD models feature slideable operator platforms and an optional safe-impact-system. The latest improvements include an optional weather-protected operator area. A newly designed entrance step together with storing boxes and a lockable cover for the dashboard with bigger colour display meet the expectations of Dynapac's future customers. Improved visibility is claimed with the optional energy-saving LED working lights, which replace standard halogen units. Also improving visibility is a new camera system, and this is particularly suited to working with big hopper inserts and mobile feeders. The camera can be mounted wherever required, and the images can be watched on the new larger colour display. Each of the new models is powered by a 196 Cummins QSB 6.7 water-cooled turbo-diesel engine, with power ratings from 110–194kW depending on the paver model. Equipped with screeds, the pavers weigh 18.5–19.6tonnes.

The firm is also offering the PaveSmart 3D package from Leica Geosystems as part of a system alongside the Dynapac PaveManager v1.0 levelling system. The sophisticated PaveSmart 3D machine control system is being offered on the new-generation SD2500C CS and SD2550C CS asphalt pavers. In addition, PaveSmart 3D v3.0 also supports all other Dynapac paver models capable of being controlled using the MOBAmatic levelling system. 265 Leica Geosystems has worked with Dynapac’s engineering team to provide a plug-and-pave interface to the new-generation SD-class pavers. Dynapac’s PaveManager 3D option offers an easy-to-use levelling solution, allowing paving contractors to minimise the costs and logistical problems associated with traditional stringline controls. The system is said to maximise asphalt surface smoothness and offers users the chance to use a mix-and-match of 3D and traditional levelling sensors. PaveSmart 3D tracks the position of the paving machine in real time, in relation to a 3D model of the jobsite, regulating steer and elevation hydraulics to produce the asphalt product directly from the original 3D designs. Designed specifically for paving applications, PaveSmart 3D’s capabilities allow asphalt paving contractors to achieve major gains in productivity as well as substantial cost savings due to the 3D precision paving technology.

717 Leeboy’s new 8616 paver features an electric screed as standard, with power from a Kubota diesel rated at 75kW and a Tier 4 Interim version due shortly. Weighing in at 8.6tonnes the machine features a Legend 815HD screed offering paving widths from 2.4–4.6m. Its hopper has an 8tonne capacity while the deck configuration is said to offer good visibility. Steel tracks can be fitted, with poly pads available as an option.

1252 Roadtec’s RP195E paver runs on rubber tracks as standard, although steel tracks are offered as well, while the RP190E is a wheeled machine sharing similar performance features. To meet the Tier 4 Interim requirements, the firm has raised the deck of the pavers slightly, as this ensures visibility, and has added sufficient space for the emissions equipment, while also improving serviceability. Visibility is further improved due to swing-out seats, while joystick controls are said to make the machine easy to operate. Four different screeds are offered (including front extending units from sister firm 2599 Carlson) to suit various requirements, while the machine has chromium carbide wear plates inside the hopper to maximise life. A hopper insert is available for working along with a Shuttle Buggy. Roadtec offers the RP195E and RP190E with a choice of 1228 MOBA or 342 Topcon paving controls, to suit customer preference. The pavers will shortly be offered with the Roadtec Diagnostics package, which is already available with the firm’s milling machines. This package uses Global System for Mobile Communications (GSM) technology with a booster kit if required. This system allows a contractor to monitor performance remotely, while the customer can also set the system so that Roadtec can assess machine health remotely and send messages when service schedules are due.

The company has still to reveal details of its European style pavers being developed in Germany but these have been based on the proven US designs and modified as required. The German-built pavers will also have European-style screeds.

Ichiro Shimada, vice president international sales for 2714 SUMITOMO Construction Machinery, said that the company intends to boost its sales in export markets, a project that has been in hand over the last three years. “Sumitomo is dominant in Japan and we have 70% market share. But the market size is limited, maybe 400 units/year. We’re putting a lot of effort into the Chinese market.”
Europe is another key market for Sumitomo and the firm is focusing on countries such as France, Poland and Switzerland, while the company has also had sales success in the Middle East including Dubai, Iraq, Iran and the UAE. The new HA60W wheeled machine is designed to meet the Stage IIIB/Tier 4 Interim emissions requirements and will be a focus for European sales. The machine is in prototype form at present and testing is still on-going, with the production machine due to be available in Europe in the third quarter of 2012. This features a novel screed design with competitive benefits over rival products and Shimada said, “Our J paver covers two classes of screed.”

The innovative overlapping telescope unit design can extend from 2.3–6m, whereas conventional units from other firms compete in the 2-5–5m or 3–6m classes. Shimada continued: “We are keen to introduce the bigger one into Europe, the 9m machine. We’ve had some successes in China with it. The HA90C will have a J screed that extends from 3–7.5m without mechanical bolt-ons.”

Bolt-on extensions can also be used as with conventional units, further increasing paving width for the new 2360 and 3075 screed models in comparison with rival designs. The units have the firm’s proven STV tamper bar and vibration features for pre-compaction, providing good finish. The 2360 screed is offered on the firm’s wheeled HA60W and tracked HA60C pavers, as well as the HTP60W tack coat machine. The 3075 screed is offered on the 22.6tonne HA90C paver, which offers paving widths of 3–7.5m using hydraulic extension and up to 9m with bolt-on units fitted.

The plans are that the 9m machine will be CE marked for launch in Europe in 2013. The firm is not considering developing a US style paver for the moment, however, as this is not simply a case of replacing the screed. North American customers also pave at higher speeds, which would require a redesign of the drive system. “If we get into the US market, we’d need something different.”

Mold board controls govern the flow of asphalt so that there is no cooling or material segregation while each screed has its own heating system. Electric heating is an option, although LPG heating remains the standard fitting on the Sumitomo machines at present. The firm works with Topcon mainly for paving control technologies and Shimada added, “Topcon is popular in Japan and very popular in Asian countries.”

Sumitomo has also developed a dual layer paving machine that features twin screeds, which has been used successfully in Japan.

Powered by a Cummins QSB6.7 diesel rated at 191kW, the Terex CR662RM paver meets the Tier 4 Interim but is 5% more fuel efficient than before. The engine features cooled exhaust gas recirculation with a diesel oxidation catalyst and diesel particulate filter (DPF) to reduce emissions. Regeneration of the DPF occurs automatically without affecting machine performance. A new cooling system arrangement features a larger radiator core size and improved airflow to increase ambient operating temperatures to 48.9°C.
To offset increased space requirements of the Tier 4i engine components, 1222 Terex engineers developed a new low-profile engine cover that slopes downward away from the operator and improves visibility. The integrated radiator ensures that clean air is drawn for cooling the engine. Components from the paver’s fume recovery system have been moved from underneath the operator’s platform to under the hood, lowering operating noise levels and improving operator comfort. The CR662RM features two 1,524mm long spread auger sections that are driven by two independent variable-speed outboard motors, which eliminate the centre gearbox drive and reduce centreline segregation. Contractors can equip the CR662RM with one of three different screed models – the diesel or electric Terex Fastach 10, electric Terex VersaScreed, and the electric or diesel Terex Stretch 20. This 3m paver delivers mainline paving widths reaching 9.1m at depths of up to 305 mm. The CR662RM features the patented Terex Smartrac rubber track drive as well as oscillating bogie wheel assemblies. The self-tensioning system is said to optimise track tension, extending life. The rubber track drive also spreads the machine’s 24tonne weight over a wide area, resulting in a low ground contact pressure.

With intelligent emissions control from the introduction of a six-cylinder Cummins diesel rated at 186kW, 1194 Vögele’s new Super 2100-3i paver is claimed to raise paving efficiency to another level, with state-of-the-art engine technology that ensures extremely low emission levels. The Dash 3 paver series gets EcoPlus, a package aimed at making significant reductions in fuel consumption and noise levels. A switchable transfer gearbox allows hydraulic pumps to be by-passed when not needed. A variable-speed fan is fitted that runs depending on cooling demand set by charge air, coolant and hydraulic oil temperatures.

Vögele Super 2100-3i operators also get a revised platform with a larger colour display. The proven ErgoPlus operating system has also been developed further for the Dash 3 pavers. The new AutoSet function enables the paver to be moved quickly and easily on the jobsite. At the push of a button, hopper sides and the hydraulic hopper front are folded up, the deflectors in front of the tracks are raised, the augers moved into their uppermost position and the screed is raised and locked in place. The EcoPlus Package includes a splitter gearbox with the ability to disengage hydraulic pumps, a variable-speed fan, and an energy-optimised tamper drive, which further reduces fuel consumption and noise levels.

There are two notable new functions. The automatic docking function called PaveDock is fitted to the Super 2100-3i and absorbs impacts from the feeder. Meanwhile any truck movements required during the feeding process are communicated to the lorry driver using a set of signals. This is called PaveDock Assistant and provides an efficient communication system for paver operator and driver of the feed vehicle.

The latest tracked asphalt pavers from 359 Volvo CE get independent travel drives and electronic traction control to help maintain productivity on slopes and around corners. The P8820C ABG can pave widths from 2.5m up to 13m and handle 1,100tonnes/hour, while the P7820C ABG paves widths up to 11m and places up to 900tonnes/hour. For Europe the pavers come with Volvo’s latest Stage IIIB-compliant six-cylinder D8 engine delivering 175kW in the P7820C and 200kW in the P8820C. In most operating conditions the Smart Power system reduces engine power and speed, resulting in fuel savings of up to 30% as well as halving noise levels. The operator’s central control panel can be swivelled, tilted and extended and houses the Electronic Pavers Management II system (EPM II), which controls the paving processes. Wide rubber clad crawler tracks have individual (electronically controlled) drives and the electronics system monitors track movement and controls motor response for accurate straight line and fixed radius work. EPM II’s Settings Manager allows operators to save settings for future recall when similar conditions are encountered and thereby reduce set-up time. The electronic system also monitors fuel consumption and alerts the operator when maintenance is due.

Meanwhile Volvo’s US style paver, the P6110C, is said to feature a low deck height and has seats that telescope over the side to improve visibility. The fumes extraction system pushes gases away from the operator while good heat control is said to ensure better mat quality. The Tier 4 Interim engine offers lower fuel consumption than the previous diesel, as well as reduced noise.