Bomag has announced a major upgrade to its BW 138 tandem rollers, integrating an advanced infrared thermal imaging system designed to automate drum watering and optimize compaction quality based on real-time asphalt temperatures. In hot mix asphalt paving, maintaining the correct temperature window is critical. If the asphalt is too hot, it sticks to the steel drum, tearing the mat; if it is too cold, the aggregate doesn't interlock, resulting in premature road failure.
The new system utilizes a forward-facing, high-resolution infrared camera mounted on the roller's front frame, just above the drum. As the machine advances, the camera continuously scans the thermal profile of the asphalt mat up to 10 meters ahead. This thermal data is processed by the roller's edge-computing module, which calculates the precise temperature gradient of the surface.
The critical innovation is the system's closed-loop integration with the drum's water spraying system. Traditional rollers rely on the operator to manually adjust the water flow based on guesswork, often resulting in either a dry drum that picks up asphalt or a flooded drum that rapidly cools the mat. If the Bomag thermal system detects that the upcoming asphalt is above the optimal compaction temperature, it automatically increases the flow rate of the water spray to create a thicker evaporative barrier, preventing material pickup. If the mat is cooling toward the lower limit, the system reduces the water flow to prevent thermal shock and premature stiffening.
During a recent airport runway paving project, the automated thermal mapping system eliminated drum pickup entirely and allowed the roller to maintain maximum compaction frequency right up to the thermal cut-off point. By removing human guesswork from the watering process, Bomag is ensuring consistent, high-density asphalt surfaces while reducing operator fatigue.
