Dynapac has unveiled the "Joint-Heat" longitudinal joint heating system for its SD2550CS highway-class tracked asphalt pavers. In multi-lane highway construction, the longitudinal joint between a freshly paved lane and a previously compacted, cooled lane is the weakest point in the pavement structure. Traditional joint construction uses a "notched wedge" or simply butts the hot asphalt against the cold edge, resulting in a density gradient at the interface. Over time, water infiltrates this low-density seam, causing the joint to ravel and the pavement to fail prematurely.
The Joint-Heat system mounts a "Cantilevered Infrared Heating Array" to the side of the paver screed, extending directly over the unconfined edge of the previously paved lane. The engineering breakthrough is the "Dynamic Thermal Bonding Control." The system does not merely apply constant heat. A series of fast-response thermocouples continuously measure the surface temperature of the cold mat edge 1 meter ahead of the screed.
The ECU calculates the exact thermal mass and ambient temperature to determine the required BTU input. It then modulates the propane flow to the infrared burners, dynamically heating the existing lane edge to between 140°C and 150°C just before the new hot mix asphalt is screeded against it. This creates a true thermal bond-welding the two lanes together at the molecular level rather than mechanically compacting a cold edge against a hot edge. This continuous thermal profiling increases longitudinal joint density by an average of 7% over traditional cold-joint methods, eliminating the permeability that causes freeze-thaw raveling.
