Best Practices for Longevity and Quality

by John Greaney

Asphalt pavement is a popular choice for parking lots due to its durability and cost-effectiveness, and correctly paving asphalt joints is crucial for durability, longevity and overall quality of asphalt projects. Improperly constructed joints are often the primary source of pavement failures, leading to costly repairs and shortened lifespan of your asphalt project. In this article, I will go over best practices for paving asphalt joints, ensuring a seamless, durable and long-lasting surface.

There are primarily two types of joints: longitudinal and transverse. Longitudinal joints run parallel to the direction of paving, whereas transverse joints are perpendicular. The quality of these joints is crucial as they are often the weakest points in the pavement.

Best Practices for Paving Asphalt Joints
Effective joint construction starts with thorough planning, knowing cold joints versus hot joints, keeping your eye on the clock in between loads as mix temperature will play a huge role with bonding. Ensure the surface to be paved is clean, dry and free of debris. Proper surface preparation is critical to ensure good bonding between the new and existing asphalt layers. When paving operations are interrupted, the existing asphalt should be saw-cut to create a vertical face. This ensures a straight, clean edge, which is essential for a tight joint, and don’t forget the tack.
Apply a tack coat to the vertical face of the saw-cut joint. The tack coat promotes adhesion between the old and new asphalt layers, minimizing the potential for water infiltration and joint separation. In some cases, particularly in colder climates, preheating the existing asphalt edge can enhance bonding. The new asphalt should slightly overlap the saw-cut edge. This overlap is then compacted, ensuring the new material bonds well with the old, creating a seamless transition. Just like paving a cold longitudinal joint, keep in mind in general for every one inch of material put down, it will compact one-quarter inch. Adequate compaction is crucial, using a vibratory roller to ensure a dense and durable joint.

When paving is interrupted and the previous lane cools, a cold joint will form. To ensure a good bond, the edge of the cold joint should be treated with a tack coat or joint adhesive before paving the adjacent lane, same as above transvers Joint. We are going to run our endgates down, creating a nice straight edge for our first pass or lane. When matching the joint, for one inch of material put down, it will compact one-quarter inch and you will want to overlap one to two inches.

When compacting the first lane for cold joints using a steel drum roller, you will want to overhang the drum six inches off the unsupported edge in efforts to compact vertically versus pushing the mix wider or away from the joint. Rolling should be done from the hot side toward the cold side on second lane locking in the joint. Always roll low side to high, and be aware of the crown in the road as you do not want to see daylight under both sides of the drum.

Paving lanes simultaneously or in quick succession while the adjacent lane is still hot ensuring optimal bonding known as hot joints is a method that provides a better bond, and is preferred whenever possible as you are matching the joint while the mix is still hot. Monitor the temperature of the asphalt mix closely — asphalt should be laid and compacted while it is within the optimal temperature range to ensure proper bonding and compaction. With hot joints you will want to keep your endgate up and level with your extension, and overlap two to three inches using the crank or tow points to adjust. If you also have grade control, many will set that up on one side as a joint matcher. Again, keep your eye on the clock as that shoulder or edge due to not being compacted will have voids. You will want to get this rolled quickly within your temperature window, which can lead to water infiltration and pavement failure.

Properly paving asphalt joints is a meticulous process that involves several critical steps: edge preparation, tack coating, joint formation, and mix temperature and compaction. By following these best practices and using the right techniques, the integrity and longevity of asphalt pavements can be significantly enhanced. Each step, from ensuring clean, straight edges to achieving the correct compaction density, plays a vital role in preventing common issues such as water infiltration and premature pavement failure. Implementing these practices and following local department of transportation and bid specs will result in durable, high-quality asphalt pavements with well-constructed joints. By understanding the importance of joints and implementing these practices, paving professionals can deliver high-quality, long-lasting parking lots that require minimal maintenance.

John Greaney is a Southwest Regional Sales Manager with Leeboy. He can be reached at john.greaney@leeboy.com