When widespread surface cracking develops on the aging pavement, an asphalt fabric overlay is a reliable alternative to costly excavation and replacement of the cracked and deteriorated asphalt.
Most cracked and distressed surfaces arise from surface water seeping through untreated cracks in the pavement. When water enters the base of the pavement, the base material can become compromised, leading to further cracking. High traffic volumes and vehicles carrying heavy loads (garbage trucks and delivery trucks can be especially damaging) can also lead to excessive surface cracking. Simply attempting to seal or applying a skin patch to these heavily damaged areas will provide only a temporary solution as the existing cracks will quickly reflect through the new surface.
Although reflective cracking cannot be completely eliminated, the use of a fabric overlay significantly slows the reflective cracking process by forming a moisture resistant barrier that prevents water from passing through cracks, joints, and the pavement itself, preserving the structural integrity of the base. In addition, the fabric forms a shock absorption layer in the asphalt. This greatly reduces tensile stresses within the pavement, resulting in a dramatic increase in the life of the asphalt overlay.
The process for applying an asphalt fabric overlay begins by cleaning the existing surface of dust, dirt, vegetation, and moisture. Low areas are filled with hot-mixed asphalt and large cracks are sealed to maximize the performance of the fabric. Hot oil is applied to the surface, followed by the placement of the fabric. Hot mixed asphalt is then installed over the fabric and compacted. During the paving process, the heat and pressure from the compaction of the hot asphalt cause the oil to soak through the fabric. This creates a waterproof membrane that effectively adheres to both the new and old asphalt pavements.
Long-term field evaluations have shown that the proper use of paving fabrics in asphalt overlays can increase pavement life up to 50%. Utilizing asphalt fabric overlays will reduce maintenance costs and improve the effectiveness of your pavement management system without the need to completely remove and replace your existing pavement.
Surface cracking is the leading problem seen with asphalt pavement installations. While asphalt pavement remains one of the best ways to pave a surface both in terms of performance and longevity, no material or process is perfect. Asphalt can begin to crack over time, so repairing those cracks in a timely manner becomes important to the health of the pavement. However, when the cracks reach a point where regular repair and patching is impractical, it might be time for the use of a fabric overlay.
Rather than ‘chasing’ cracks around the asphalt time after time, a fabric overlay gives you a chance to significantly slow down the development of cracks without having to install a completely new piece of asphalt. Fabric overlays are a popular option for older asphalt surfaces because they can breathe new life into a piece of pavement that was starting to head downhill. When a fabric overlay is used properly by an experienced asphalt contractor it can result is a significant addition to the expected lifespan of the surface.
The Cause of Cracks
In most situations, cracks in the surface of your asphalt are caused by water. When surface water makes it way down through small cracks that are present in the asphalt, those cracks will usually get larger – and more cracks will develop in other parts of the pavement as well. Water is not a friend to asphalt when it gets in under the pavement and is allowed to do damage. You want to keep as much water as possible on top of the asphalt rather than under it, which is why using a fabric overlay makes so much sense.
A Water Barrier
When a fabric overlay is applied, it can act as a barrier to keep water from seeping down through the cracks of the asphalt moving forward. Pieces of asphalt pavement without a fabric overlay simply don’t have this protection, and they are always going to be at risk of cracking as a result. Of course, fabric overlays don’t completely eliminate the possibility of surface cracking, but they do go a long way toward preventing this kind of damage from appearing in your asphalt. And, when surface cracks do show up, having a fabric overlay in place is likely to help prevent those cracks from spreading.
The Process
In working with an asphalt contractor, it may be determined that a fabric overlay is the best option for your pavement. When that choice is made, the process of installing the overlay will go roughly as follows.
- To get started, the existing asphalt surface is going to be cleaned thoroughly. Any dirt that is one the asphalt will need to be washed away and any vegetation that is growing up through the cracks will have to be removed as well.
- With the existing surface freshly cleaned, big cracks in the pavement will be sealed up and any low spots that might exist will be filled in with new asphalt. The goal here is to create the best possible surface for the fabric overlay to cover.
- Before the fabric is put down, a layer of hot oil is added to the asphalt. That oil will eventually be forced to soak through the fabric as the installation process is completed. When the oil has successfully soaked into the fabric, the overlay will become a waterproof layer.
- With the fabric and oil both put down, the process is completed with the addition of a new top layer of asphalt. This top layer is compacted just like any other asphalt installation, and the fabric is effectively sandwiched between the old asphalt and the new.
For a talented crew of asphalt workers, this is a relatively simple process to complete. It is certainly far less expensive than having the whole piece of pavement taken out and replaced, and you can expect the final product to extend the life of the surface by 50%.
It’s About More Than Water
A big part of the benefit of using a fabric overlay is the ability to keep water from getting into places where it doesn’t belong. However, that isn’t the only performance characteristic that you will enjoy once this kind of solution is used on your pavement. The use of a fabric overlay is also going to help to spread out the stress that is placed on the pavement by heavy loads, as it can act as a shock absorber. Therefore, not only will you experience less cracking due to water damage, but you should also see less cracking from the stress of day to day use.
Bring the Repairs to a Stop
Yes, it is going to be more expensive in the short term to install a fabric overlay than it would be to simply repair cracks as they pop up. However, if you keep repairing cracks over and over again as the years go by, you will likely spend more money in the long run by taking that approach. Also, there is a significant amount of time that will be spent arranging repairs when you frequently have new cracks show up in your pavement. By taking the step of installing a fabric overlay on your pavement now, you can dramatically slow down the rate of repairs for many years to come. No one wants to constantly think about fixing their driveway or parking lot, so consider getting out of that cycle by opting for a fabric overlay project rather than basic crack filling and sealing.
The ability to use something like a fabric overlay is another example of why asphalt is such a popular paving material. Even when an asphalt surface is starting to show its age, you can turn to a system like a fabric overlay to extend its life and avoid going through a full reinstallation. As long as your base layer remains strong underneath the pavement, you can continue to repair and resurface your asphalt as necessary. To learn more about whether or not a fabric overlay project is a right option for your needs, you may wish to contact an asphalt contractor in your area.