This roller automates vibration frequency depending on the amplitude as set by the operator.
BOMAG offers intelligent compaction, which controls the compactive effort based on density levels being “read” by the machine.
Ingersoll Rand employs what it calls SMART drum technology to automate the following:The balance between vibration frequency and amplitude—the amount of vertical movement of the drum.Roller speed control, to maintain travel speed in an optimum range and provide between 10 and 14 impacts per foot.The on-off status of vibrations depend on travel speed. When the operator slows his travel speed to change directions, the vibrations will shut down as a certain speed is reached. When travel speed increases, vibrations resume.Water supply to the drum is automatically regulated based upon travel speed.
All of Ingersoll Rand's HFA machines—those offering both high amplitude and high frequency—have SMART drum technology. (The company also offers machines that deliver high frequency or high amplitude.) Ingersoll Rand manufactures HFA compactors in 11-, 13-, and 15-ton sizes, and this year will introduce a new 9-ton roller. All four are part of the company's Large Asphalt Product Development series.
SMART technology allows the operator to select one of eight different amplitudes, based on the thickness of asphalt mat and the conditions of the project. “Then the machine automatically selects the frequency that's the optimum for that amplitude,” said Gallant. That selection is made to provide the maximum rolling speed and still achieve 10 to 14 impacts per foot.
For thicker lifts of asphalt, the compactor will use lower frequencies at higher amplitudes. For thinner lifts, it goes to higher frequencies at lower amplitudes. A label on the Ingersoll Rand machine recommends amplitude settings for various thicknesses.
An optional TransTech Pavement Quality Indicator also is available on Ingersoll Rand's HFA models. When the operator hits a switch, the density indicator deploys and takes a reading that is displayed on the operator's console. This way, the operator can assure that full density is achieved–and that the contractor will receive 100% of pay–while the asphalt is still in a compactable state. “We believe the operator needs to know density and control the roller accordingly,” said Gallant.
What's coming next to the United States, said Deahl, is a roller equipped with an intelligent compaction system combined with a global positioning system. The roller will transmit mat stiffness and location information to an analysis center, which bounces back information to the roller about onsite densities by location. BOMAG has used this technology on single-drum vibratory rollers for soil compaction. Information about high- and low-density areas is stored on a computer disk.
“That technology has been put on double drum (asphalt) rollers in Europe, but I don't know of any manufacturer in the United States that is doing it with double drum rollers,” said Deahl. “That's the next step here in the United States.”
—Daniel C. Brown is a freelance writer in Des Plaines, Ill.For more information
BOMAG Americas www.bomag.com
Hamm Compaction Division (Wirtgen America)
Ingersoll Rand www.irco.com