LONGITUDINAL JOINT CONSTRUCTION TECHNIQUES FOR ASPHALT PAVEMENTS

Thirty hot mix asphalt (HMA) test sections were constructed in Michigan (1992), Wisconsin (1992), Colorado (1994), and Pennsylvania (1995) to evaluate the effectiveness of twelve different longitudinal joint construction techniques. The performance of these test sections was evaluated in 1996 after one to four years in service. The joints with high densities generally show better performance than those with relatively low densities. The Michigan joint technique (12.5 mm vertical offset and 12:1 taper) appears to have the best potential of obtaining a satisfactory longitudinal joint. The cutting wheel and the edge restraining device techniques have good potential but are too much operator dependent to obtain consistent results. Among the three different joint rolling techniques used in all four projects, rolling the joint from hot side generally gave the best performance followed by rolling from hot side 152 mm away from the joint. Paver manufacturers should consider modifying the paver design to obtain a Michigan type, high density unconfined wedge in the lane paved first. Highway agencies should specify minimum compaction levels to be achieved at the longitudinal joint.