Compacting the soil

High productivity and value for money are two benefits claimed by the new generation of soil compactors - Mike Woof reports

The market for soil compaction machines looks to be growing more competitive as new manufacturers enter the sector. This is particularly noticeable now that Chinese firm 269 LiuGong has moved into the sector. Meanwhile new design concepts are also allowing firms to develop much larger and more powerful machines than ever before. The choice for contractors is a wide one and manufacturers are likely to become more aggressive when it comes to selling units than in years past, with the potential of some good deals for customers.

One of the most visible introductions for the soil compaction market comes right at the top of the performance class however. 172 Bomag finally unveiled the production version of its massive 32tonne machine soil compactor, first shown as a prototype in 2007 when strong interest prompted the firm to develop a production version. The new BW332 is now the heaviest single drum roller on the market and features a 2.4m wide polygonal drum, which helps deliver the huge compaction forces the machine generates, as tests showed a conventional smooth drum would not work efficiently. Unlike a conventional design, the patented polygonal drum will not sink into the ground and does not dissipate vibration energy at the surface. Compaction forces are said to be directed vertically into the material instead and without vibration losses while the drum also provides optimum traction as well as low rolling resistance. BOMAG claims that the BW332 features an overall performance some 50% higher than the firm's 26tonne BW226. This machine delivers a centrifugal force of 750kN and a working width of 2.4m. According to BOMAG, the BW332 offers 50% more compaction performance than its 26tonne BOMAG BW226, which was previously the heaviest soil compactor on the market.

BOMAG claims that the BW332 offers high productivity and major cost reductions for large earthmoving jobs as it allows soil compaction to be carried out in a single stage. The machine is equipped with BOMAG's VARIOCONTROL vibration system, which automatically adjusts vibration to soil stiffness for optimum and uniform compaction.

Tough competition will come in the compaction segment from China and the first company to enter the worldwide market on a major scale from this country is LiuGong Machinery Corporation. The firm's CLG612HIII is a hydrostatic single-drum vibratory roller that can be used for compacting base and sub-base fill in roads. Power comes from a 196 Cummins QSB4.5 diesel engine that delivers 116kW and meets Tier 3/Stage IIIA emissions regulations, meaning that it can be sold in North America and Europe. Heavy duty Sauer 90 series hydraulics are fitted and are said to provide a smooth power delivery and allow speeds of up to 12km/h. The roller is available in smooth drum, smooth drum with bolt-on padfoot shells and dedicated padfoot drum versions to match different soil conditions. Other features include dual amplitude for better compaction performance in a wide range of operating conditions as well as an optional density meter.

A more established range for the mid-sized soil compaction market comes from 2394 Volvo, which continues to invest in the range it bought from Ingersoll Rand. A series of upgrades have been made to its soil compaction machines to boost performance and increase capacity, while the firm is also introducing new models to expand the range. The SD115D and SD115F and SD130D, SD130DX and SD130F are all completely new machines that take the place of earlier models in the line-up, while the SD160D and SD160F variants are upgrades of existing machines.

The SD115D features a smooth drum while the SD115F has a padfoot drum, with both machines weighing around 11.5tonnes and being powered by diesels rated at 97kW. The SD130D and SD130F also feature smooth and padfoot drums respectively and weigh in at 12.8tonnes, with power from diesels delivering 119kW.

A key feature of the new SD115 and SD130 compactors is in the smart power mode, which is designed to match engine output to the working application. When switched on, the automatic control can reduce engine speed but can also be turned off if required. This sophisticated system is designed to be used on the Volvo compactors featuring five vibration settings and will also govern engine cooling accordingly through control of the electric fan. The smart power system also reduces exhaust and noise emissions and minimise fuel consumption, with this last feature making it a useful setting for many contractors keen to cut machine running costs. A new generation of engines will ensure high performance combined with low exhaust emissions and noise output.

The machines come with a choice of two preset and five optional frequencies (there are five settings as standard on the SD130 and SD160 variants). In addition, the new models have dual amplitude settings and according to 359 Volvo CE, this range of options means the machines offer the highest compaction forces in their class. High power to weight ratios and high dynamic forces are claimed, along with low centres of gravity, good gradeability and a sophisticated traction control package that helps maximise performance on slopes.