Innovations for asphalt compaction

Asphalt compaction advances were unveiled from an array of manufacturers at the INTERMAT 2012 event - Mike Woof reports

With new emissions legislation being introduced, manufacturers are rolling out a range of new asphalt compaction models designed to meet the latest requirements. These include both large rollers for high-production highway operations and compact machines designed for the rental market and suited to urban applications, with the latter segment becoming particularly competitive at present.

Swiss-based 6791 Ammann offered a huge array of re-vamped asphalt compactor models. Its new range of lightweight tandem rollers includes 13 models with operating weights from 1.2–4.5tonnes. The ARX models are said to feature better integration between 7139 Yanmar engine and Rexroth hydraulic system components and can operate at lower engine rpm without compromising on compaction performance. The result is improved fuel efficiency and lower working noise levels. A slimmed-down chassis and lower profile engine canopy afford better visibility to the drums. Improvements include a re-designed operator station with vibration insulation, a simple and clearly laid out instrument panel and multi-functional drive lever.
Moving up the size scale, the AV 120 X asphalt roller is the latest addition to the family of articulated tandem rollers produced by Ammann. Equipped with 1880mm wide drums, the AV 120 X has been produced for efficient compaction on asphalt mixes and binder courses. The machine offers an unobstructed view of the drum, a sliding and rotating operator’s station and a drive system with two hydraulic pumps that is claimed to deliver improved driving and rolling properties. The 11tonne machine is powered by a 196 Cummins QSB 3.3 engine and delivers a static line load 29.6 kg/cm.

178 Caterpillar has revised its asphalt compactor range with Stage IIIB engines, revised drum options and a new cab layout. The new CB44B and CD44B tandem rollers compete in the 7–10tonne size class, while the CB54B and CD54B compete in the 8–11.3tonne class. Revised cabs now give better sightlines to the drum edges and while the lateral side-shift for the operator’s seat has been retained, the previous 180° rotation is now extended to 360° rotation, giving the operator more freedom. All instrumentation and controls are now integrated into both armrests, which move with the operator when the seating position is moved. Cat has also engineered full auto-correction of controls as the seat is spun, so steering and travel functions correspond to the way that the operator’s seat is facing. The asphalt compactor range can also be equipped with Cat’s optional Compaction Control, and using infra-red sensors on both ends of the machine, this allows mat temperature and number of passes to be relayed to the operator via an in-cab screen. This system boosts night-time performance, and also records information for
future process analysis and quality control documentation.
The four new rollers are said to perform well in vibratory or static modes, enabling a single machine to perform breakdown, intermediate and finishing work. The B-Series' machines can be equipped with solid- or split-drum designs as required. The latter design is said to deliver good mat quality in urban environments and confined working areas where frequent turning is required. The solid drum offers expanded vibratory choices to match amplitude and frequency requirements and is said to perform well in high-production street and highway applications.

The CB44B is equipped with 1.5m drums and a Cat C3.4B engine rated at 75kW. The CB54B has 1.7m drums and features a larger C4.4 engine rated at 98kW. The powertrain comes standard with ECO-mode and automatic speed control, saving fuel, reducing sound levels, and lowering operating costs. The CD44B and CD54B rollers feature front and rear-pivoting drums and four steering modes. With its maximum offset, the CD44B provides a compaction width of 2.8m while the CD54B has a compaction width of 3m at full offset. The B-Series' tandem rollers offer a variety of vibratory options.

228 Hamm has launched the smallest combination roller in the HD CompactLine roller range, the HD10C VT1m. With a working width of 1m and weighing 1.5tonnes, the new model is being launched with a permanent all-wheel drive as standard. According to Hamm, the main benefit of these rollers is the outstanding climbing ability, whatever the situation, outstripping every other roller of this size. The new range also includes the firm’s larger and more productive 13 HD+ models, which range in weight from 9–14tonnes. These machines all feature a three-point swivel joint providing optimum weight distribution and high directional stability. The company claims that productivity is high, along with a high-quality working finish. The firm continues to develop its innovative compaction monitoring technology too, which is available with these machines and allows optimum efficiency on-site. Using the package ensures that an asphalt mat can be compacted efficiently and productively, and without risking either over or under-compaction.



For the rental market the new compactors from JCB are the VMT380 and VMT430 models. These are said to offer high operator visibility, comfort, safety and performance. Tapered frames ensure good sightlines while both models are powered by 2.2litre 2278 Kohler diesels mounted in the front chassis section and rated at 34.6kW, with large fuel and water tanks that are said to be class leading. Travel speed is claimed to be 10% higher than competing machines. Vibration frequency is 66hZ and amplitude is 0.4mm, while vibration can be selected on front, rear or both drums as required. Both models are offered with a choice of drum widths of 1.3m or 1.4m. The VMT380 weighs either 3.8tonnes or 3.9tonnes while the VMT430 weighs 4.2tonnes or 4.3tonnes, depending on whether the 1.3m or 1.4m drums are fitted. The VMT380 replaces the earlier VMT390, while the VMT430 replaces the VMT400. The drums can be offset if required, while other features include hinged scraper bars and a maintenance-free centre joint.



Designed for smaller compaction projects, Volvo’s DD25 and DD25W are double drum compactors that fit into the 2.5 tonne weight class. Adjustable frequency is available from 3,300vpm/55 Hz to 4,000vpm/67 Hz, achieved by moving the throttle. Drums are machined to be perfectly round, said 2394 Volvo, while the outer 20mm of each drum is chamfered and the edges are given a 9mm radius. These features contribute to a smooth rolling finish that will not leave marks on the asphalt surface. Both drums also include a pressurised water system that provides a constant flow to the drum surfaces. The DD25 compactor uses a 24.8kW three-cylinder diesel engine, and an integral safety system will shut down the engine and apply the brakes should the operator get off the seat.