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FAQ's

FAQ's

What causes asphalt failure?

 That is a loaded question! However, asphalt failure can be linked primarily to any one or the combination of the following:

• Excessive load or stress factors (heavy trucks, trash trucks)

• Water erosion or seepage

• Inadequate thickness or "section" of asphalt or asphalt and base material

• Poor subgrade (bad soil, improperly prepared subgrade)

Should asphalt be replaced once cracking appears?

It depends on the type of crack. Cracking can be caused by a number of factors, including ground movement and asphalt shrinkage. Generally these types of cracks should be filled with the appropriate crack filler and maintained on a regular basis. The primary concern is to keep moisture from penetrating the crack and undermining the subgrade under the asphalt.

Another type of crack is what is known in the industry as "alligation", or alligator cracks or spider web cracks, aptly named for their resemblance to an alligator's back or spider webs. These cracks indicate asphalt failure and the asphalt should be removed, the subgrade re-compacted and the asphalt replaced. Left unchecked, this type of cracking will spread.

Are there different types of asphalt?

Yes. Most asphalt is primarily rock and oil; however, there are asphalt mixtures that utilize different additives, such as rubber. For the vast majority of asphalt paving, conventional rock and oil is used. Incidentally, the proper term is asphaltic concrete with asphalt-grade oil being the defining binder agent for the mixture. There can be differences in the size of aggregate or rock and differences in the grade of oil to optimize the "how" and "why" the asphaltic concrete is being used.

Why do cracks reappear even after they have been filled?

As mentioned earlier, ground movement and shrinkage causes the cracks that typically get filled. The movement that caused the initial cracking will continue and cause subsequent cracking. Also, traffic will increase the likelihood of subsequent cracking. Picture the cracked asphalt as a series of pieces similar to that of a puzzle - as vehicles go from piece to piece, the weight of the vehicle is being transferred from one piece to the next, causing slight up and down movement at the crack. A filled crack will begin to open up as these forces work against it.

What is sealcoat and why use it?

Sealcoat (or slurry seal) is a product that is designed to extend the life of asphalt and increase the aesthetics of the asphalt surface. As asphalt ages, it oxidizes and becomes brittle. It also is prone to erosion from rain, irrigation run-off and traffic patterns. Sealcoat is designed to protect asphalt from oxidation and act as a wearing course for the asphalt. Additionally, as asphalt ages it turns a dull gray color. Fresh sealcoat will dramatically change the look of asphalt from old, tired and gray to new, fresh and jet-black.

What is road slurry and is it the same as sealcoat?

No. Road slurry is a familiar term used to describe emulsion-aggregate slurry, a specific type of asphalt coating application designed primarily for streets and highways. Road slurry is composed of emulsion (oil), water and aggregate (coarse sand) and is made by combining these components in a pug mill. All of the components are mixed at the job site and applied immediately after mixing. Sealcoat is made from emulsion, mineral fillers and fibers. Sealcoat is proprietary, meaning several manufacturers make and market their own sealcoat under trademarked names. All sealcoat is similar in composition but not equal in quality. Sealcoat is made in large batches and typically stored in tanks until used. Sealcoat is better suited for parking lots, walkways, playgrounds and any asphalt surface where aesthetics are important. Road slurry is a thicker, heavier application than sealcoat and therefore more durable, but it does have its limitations. Road slurry is prone to tearing and scuffing caused by sharp or tight vehicle turns, so parking lot applications are not recommended (although certainly done when appropriate). Road slurry also tends to turn gray, as does asphalt, while sealcoat will actually wear away through to the existing asphalt.

What are the benefits of latex added to sealcoat?

Latex or polymer modifiers have been shown to increase the longevity of the seal, increase drying times and help prolong color retention. Although latex does add to the cost of sealing, over time the added costs are justified by increasing the time intervals between seal applications. Latex is also beneficial for emulsion aggregate slurries for the same reasons mentioned.

Is it beneficial to have a maintenance program for pavement surfaces?

A good maintenance program for your asphalt pavement surface will extend the life of the surface. Filling cracks and making necessary asphalt repairs on a routine basis will halt further deterioration. Periodic sealing (every two to three years depending on traffic levels) will extend the overall life of the pavement as well as renew the look of your property overall.