A surprise among the 15 new products on the stand of Sweden''s Dynapac was a new medium range soil stabiliser, the DS400. This high production machine features a 2.5m working width and working depths of up to 540mm and is suitable for water injection, emulsion or foam bitumen applications.

The new stabiliser can use a variety of different tools to suit conditions and requirements. It can also be adapted for recycling applications when fitted with a spike drum.

Joachim Untiedt, president, business area, heavy compaction, described the machine as ''correctly balanced with even weight distribution.'' It travels at 20km and is powered by a 400kW engine. Applications will extend from motorway construction and road maintenance to car parks and industrial use.

Ronald Kok and Joachim Untiedt the DS400 is correctly balanced.

Continuously adjustable rotor speeds between 90 – 160rpm allows the stabiliser to adapt to every possible site condition. A planetary reduction gear with separate cooling for the rotor drive provides maximum torque with a minimum of wear and maintenance.

The speed and cutting depth is automatically adjusted by the computer for optimised production. Untiedt said the patented Cover Divider System allows the operator to change the size of the mixing chamber independently of the working depth.

The variable chamber also ensures improved results with thinner layers as well as adapting to the lower mixing volumes.

Within the mixing chamber, a drum ensures that the specified mix is met. Electronically controlled injection systems provide full control over the amount of fluids injected into the specified material to ensure the correct water/emulsion content.

The DS400 is highly maneuverable and has a 4.23m internal turning radius/8.02m external turning radius plus, with four different steering modes – front, rear, combined and crab – the agility of the stabiliser is further enhanced. The new stabiliser includes a large windscreen and glass-panelled doors to provide excellent vision of the working area. This helps the operator to minimise overlap between passes and maximise productivity.

All critical process functions are centralised with a multi-operational joystick for total control and all information presented on a coloured screen within the cab.

The unit also includes two rear view colour cameras, one viewing the area in front of the rotor and one viewing the stabilised material behind the rotor to offer enhanced productivity and safety.

"The new Dynapac DS400 is the result of 20 years experience," added Untiedt.
Three new high frequency (HF) tandem asphalt rollers covering the 10t to 13t range were also  introduced by Dynapac.

The CC424HF, CC524HF and CC624HF replace Dynapac''s popular CC422, CC522 and CC622 machines. The first models of the new range are primarily aimed at larger projects such as highways and airports.

There are a number of features to make servicing quick and easy. Use of a double pump vibration system eliminates the need for a vibration valve, making the system more efficient, aiding servicing and reducing fuel consumption. Both pumps – one for the front drum and one for the rear – can simply be shut off.

The new models have operating masses ranging from 10.5tonnes to 12.6tonnes, with the weight split evenly between front and rear drum modules.

The machines have features such as ''soft'' starting and stopping to prevent bowing or cracking in the asphalt layers; allowing even an unskilled roller operator to start and stop without leaving marks. As a safety feature, the machine will drop out of the ''soft'' mode and brake immediately if the lever is moved quickly, signalling the need for an emergency stop.

Machines can also be fitted with an optional off-set drum. Models in the range are designed for use on both thin and thick asphalt layers. Thin layers with high stone content cool off quickly and so need to be compacted fast, but use of a high amplitude risks crushing the stone. Dynapac recommends a high frequency and lower amplitude.

A key feature from Dynapac is the decision to place the engine on the rear module, which gives less noise and no heat to the operator''s platform. The position also improves access for servicing.

Dynapac also showed two new screeds - the new Svedala Demag EB51/Dynapac VB510 and the larger Svedala Demag EB60/Dynapac VB600.

The EB51/VB510 offers an increased basic width of 2.55m which is hydraulically extendable up to 5.10m, by use of extension parts a maximum working width of 8.80m is achievable. The larger EB60/VB600 has a basic width of 3m and is hydraulically extendable up to 6m – providing extended working widths 9.70m.

The company says the larger 380mm deep screed bottom plates on both models ensure better surface quality which, together with improved gas heating by an optimised exhaust air excavation system – for the gas heated version – or an improved heat dispersion with curved heating elements (electrical version) offer ''excellent laying results.''

Dynapac also launched new software for the optimisation of asphalt compaction. The software runs on a cab-mounted computer, helping operators achieve the ideal rolling pattern by keeping track of the number of passes and showing temperatures in the asphalt.

The Dynapac Compaction Analyzer for Asphalt (DCA-A) is an option for the newly-launched CC424, CC524 and CC624 articulated tandem rollers. It can also be retrofitted to older machines.

The introduction of DCA-A follows the launch in 2004 of similar software for use in soil compaction. DCA-A has been developed to give operators real-time information about the rolling, enabling them to plan their next passes taking account of the current temperature of each area.

With DCA-A, operators can see the results on the coloured graphical display, highlighting at a glance which zones need further compaction. Without DCA-A, they have to remember in detail how many passes have been carried out in each area. The system is used in conjunction with a global positioning system (GPS) to track the machine''s location, enabling accurate recording for each section.

DCA-A incorporates readings from temperature sensors at different spots around the roller. Keeping tracking of the temperature guides the roller operator to work in critical areas, which are cooling off and avoid those that are still too hot for compaction.