Proper Pavement Preservation

When you are sweeping a parking lot or road, inevitably, you will come across a pothole as well as cracks in the asphalt. If a car is damaged because of a pothole, the car owner can file a claim against the property owner or city.

If you notice these issues while sweeping, you can save your client money by educating them about the cracks or pot holes and offering your services to make the necessary repairs. The affected areas should be free from all dirt and debris, so sweeping before you repair is ideal.

“The cleanliness aspect is the key to success in making long lasting repairs,” says Adam Beres, manager of sales and procurement for Marathon Equipment Inc. located in Ontario, Canada. “You can’t make a lasting repair to asphalt without having the affected areas cleaned. Use a good sweeper before any type of repair is made; there can’t be any loose rocks or other foreign materials. If you are repairing cracks in asphalt, be sure vegetation and loose debris is removed prior to applying any hot melt asphalt crack sealant.”

Infrared

There are guidelines for what kind of method you use to repair damaged asphalt. According to Beres, infrared works best on alligator cracks or anything smaller than ¾”. Infrared has a lot of positives: it costs less, because it is reusing the material that is already there; it’s better for the environment for the same reason; and it’s portable.

The portable, walk-behind units are affordable and easier to get into smaller areas (3’x3′). Marathon units run on propane only and do not require any additional power source. With the fluctuation in asphalt prices, infrared can be a great cost-saving solution. “We manufacture a wide range of infrared heaters from the portable walk behind to our larger 4’x8′ trailer mounted units for larger repair areas,” says Beres.

Crack Sealing

If the damage to the asphalt is between ¾” to 1″, then using a hot melt rubberized crack sealant is a good option.

After removing all vegetation and foreign materials from the crack with an appropriate pick or hand tool, it is recommended to cut the crack (called routing) with an asphalt crack router to expand the crack. This will allow you to determine whether or not backfilling with a backer rod is needed because of erosion. A routed crack also promotes a better bond to the affected area as the rubber sealant won’t be pushed out when cooler weather causes the working crack to contract.

Next, clean the routed, prepped crack using your sweeper to clear away left over debris. Finally, a good quality hot melt sealant can be applied to the crack to finish the repair.

“Marathon offers several crack sealant melter solutions,” notes Beres. “There are melters ranging from 10-gallon capacity for smaller repairs all the way to our 400-gallon trailer mounted units featuring a unique heated hose and wand assembly to apply the crack sealant instead of manual application with traditional pouring cones or pots.”

If you are working in an area that needs to be cleared for traffic, a liquefied product can be applied to your hot melt sealant to eliminate tracking while the sealant sets up.

Marathon also suggests that the surrounding pavement be in 70 percent good condition. Good candidates for crack sealing should not be part of web cracks, show no branching, show no severe vertical distress such as lipping or cupping. Lateral cracks, longitudinal cracks, joint cracks, and block cracks with low or moderate condition are considered good candidates for crack sealing.

Hot Mix

If the hole or crack is larger than 1″, then you will most likely need to use a hot mix. Using it with infrared will help save you materials, but you will need to add asphalt to fill in the hole. “Hot mix is simple to do,” says Beres. “It’s durable, long-lasting, and the preferred method.” With hot mix, you sweep out the debris, preheat the asphalt (some use a hand held torch), and spray a tack coat (emulsified asphalt) to promote a good bond. Finally, it is packed down using a hand tamper or vibratory compactor.

“Hot mix is a better option than cold patch,” says Beres. “A lot of people use cold patch out of convenience, but it starts eroding quickly.”

Beres recommends a heated asphalt hauler to transport hot mix asphalt from the asphalt plant to the repair site. “Many asphalt plants’ hours of operation do not coincide with your working hours, so having a hot mix transport trailer is a valuable piece to invest in as you can store the mix on your own site, cut the product into cakes and use at your convenience by reheating with the hot mix transport unit.”

When using infrared, Kasi Infrared offers these tips:

Heater Placement

Make sure the infrared chamber is properly positioned over the repair. Square off the area that is to be restored ensuring that all edges are at least 6″ away from the damage. An additional 6″ perimeter of the heated surface needs to be left undisturbed. This will ensure that when the repair is rolled, the hot asphalt in the restored area is fused to the hot existing road eliminating seams. If the damaged area is too large to be contained within the 8′ x 6′ heated area, consecutive heats can be used to restore the area. For a large repair, work in a grid pattern moving clockwise.

Heating Time

Depending on what heater you are using, your times will vary. In 60 degree weather, a Kasi Infrared heater takes about eight minutes to heat the asphalt pavement to 325 degrees softening it to a depth of two inches.

There are three variables that determine your heating time: material, moisture, and mother nature.

Not all asphalt is the same. Mix design and age are factors. The age of the asphalt effects what percentage of the maltenes or light oils has oxidized out. The dryer the material, the longer it takes to heat. The larger the stone the longer it takes to heat. A ¾ inch binder mix can take as much as 2 to 3 minutes longer to soften than a ¼ inch top. The color of the asphalt is another factor. Because infrared rays must be absorbed into the asphalt, the lighter the color, the longer it takes to heat.

Infrared should not be used to remove standing water. However, it will remove moisture from wet pavement. Depending on how porous the asphalt is, will determine how much moisture is in the pavement. The amount of moisture in the pavement will determine how much additional time it takes to properly heat.

Wind and temperature both effect your heating time and the amount of time you will have to work with the asphalt once it is heated. It takes longer to heat the asphalt if it is 30 degrees than it does if it is 70 degrees. Once the infrared heater is removed from the patch, the wind and temperature will influence how much time the crew has to complete the repair. They will need sufficient time to rake, rejuvenate, add material, lute and roll the patch before it cools off.

It is extremely important that the pavement is heated for the proper length of time. If the heater is not on long enough, the asphalt will not be softened deep enough to ensure a proper repair. If the heater is down too long, then the asphalt could burn which will ruin it. Please note that simply removing the ruined asphalt will not correct the problem. Remember that in order to ensure a seamless restoration, it is necessary to leave at least 6 inches of heated asphalt undisturbed. If that asphalt is burned then the seam will fail.

Scarify

Once the heater is removed, the damaged area must be squared off and scarified. To square it off, take the back edge of a steel asphalt rake and cut into the asphalt. Push that material into the center of the repair. Once the outside edge is set, turn the rake over and deeply scarify the entire area. At least 2 inches of asphalt should be disturbed. Leave the area roughly level with a slight trough at the edges.

Rejuvenate

Age and sunlight cause a percentage of light oils in new asphalt to oxidize out over time. We recommend that a small amount of “maltenes” rejuvenator be applied to the existing asphalt at this time. This is not acting as a tack coat. It is simply replacing the oil that is lost from weathering.

Add maltenes recycling agent using a ratio of 1:1 with water. Distribute the solution well using a commercial grade sprayer at a rate of 8 ounces per square yard of heated area including the heated undisturbed area around the perimeter of the repair. The application should take place after the area has been scarified and just prior to the addition of new asphalt. The infrared repair contractor shall provide TDOT 411E or D mix at plant mix temperature (275-325 degrees Fahrenheit) to be added to the repair to bring the area up to grade with the existing road.

Using a good quality commercial hand sprayer, apply a light coat of the rejuvenator over the entire area, including the edges.

Add New Asphalt & Finish Raking

In order to ensure grade and a level patch, new material will need to be added to the repair. You will want to ensure that the restoration closely matches the surface texture. Determine what type of material is the original surface and what type of new material is being added. You would not want to add 3/8″ top mix to a surface made up of overlay sand mix. All hand work requires special effort to ensure that the material is not segregated with all the stone on top.

The raker determines how much asphalt is needed and the material is then wheelbarrowed from the reclaimer patch. The virgin asphalt is raked evenly throughout the patch being sure to pull this new material into the trough created around the edges. The entire patch is then luted smooth and level.

Compaction

The asphalt is now ready to be compacted. We strongly recommend that a roller is used in lieu of a plate compactor. It is important to have sufficient total applied force to ensure proper compaction.

There are a number of quality single drum, vibratory walk behind rollers which do an excellent job. It is recommended that a total of at least 2,000 lbs. per square inch applied force be used. As soon as the raking is finished, begin rolling immediately.
The rolling pattern should always begin with the edges. This is to seal the seam between the repair and the existing pavement. Use approximately 2 inches of the drum to pinch the new asphalt to the existing road. After the edges are sealed, the remainder of the patch is rolled.

Finish

After the rolling is completed, you may want to dust the repair with stone dust or some other fine material. This removes any residual tackiness and allows the repair to immediately accept traffic. Sweep up any mess, pack up the tools, remove the traffic protection, and you’re finished.

Story by Jennifer Taylor

Resources

For More Information:
Kasi Infrared, visit www.kasiinfrared.com
Marathon Equipment Inc., visit www.marathonequipmentinc.com