Vibratory Pneumatic Tire Roller
The roller has been used on various types of paving projects in the United States since the first production unit was introduced in March 2003. For the evaluations conducted on normal paving operations, the VPT roller was used in the intermediate rolling position after breakdown rolling by a high-frequency double-drum vibratory (DDV) roller. Based on the evaluation of results obtained at San Francisco International Airport, King City, California, and Traverse City, Michigan, the following conclusions were reached.
Introduction to equipment
First, the minimum required density of the pavement was significantly exceeded with a combination of a high-frequency DDV roller and a VPT roller. Second, a vibratory pneumatic roller weighing only 9,350 kg (20,580 lb) and making six roller passes at medium amplitude achieved the same level of density as a conventional static pneumatic tire (SPT) roller weighing 27,270 kg (60,000 lb) and making 12 roller passes. It is obvious that the VPT roller is more versatile and efficient than a much heavier SPT roller. Third, the density distribution measured by cores cut from the pavement show that the density in middle or bottom portion is higher than that in top portion. It is believed that the density in top portion was lower due to excessive compactive effort applied during breakdown rolling when the pavement surface temperature was relatively low.