Asphalt Maintenance

Paving and seal coat


Why Sealcoat?

“Just as paint can protect wood and metal from the elements, sealer protects asphalt,” says GemSeal’s Lee Lowis. “It also helps to keep the pavement flexible by sealing in the asphalt oils.

The reason to sealcoat asphalt pavement is to extend the life of the pavement investment. It’s as simple as that.

Whether contractors are sealcoating driveways or parking lots, the original pavement investment by customers is significant. So anything contractors can do to slow the rate of pavement deterioration improves the life cycle costs of that pavement investment. And sealcoating – as part of a comprehensive pavement maintenance program – plays an important role in extending pavement life.

Sealcoating is essential in pavement preservation and extending the life of your asphalt pavement,” says Greg Houser, vice president of research and development for Neyra Industries. “There are many benefits of sealcoating asphalt, including improving visual aesthetics, resisting oxidation from the sun, replacing eroded surfaces, extending the life and optimizing the overall value of the asphalt pavement.”

“Whether it’s a refined tar sealer or an asphalt-based sealer, you want to put down a layer to slow down the degradation of the hot mix asphalt pavement,” says Rob Vance, vice president of sales and marketing for Vance Brothers and current chairman of the Pavement Coatings Technology Council (PCTC). “Is it going to prevent the deterioration from happening? No. But it will slow down the deterioration.”

Basically, the reasons for sealcoating revolve around the limitations of the asphalt concrete pavement on which it’s used. In his “Basic Sealcoating Principles” session at the 2015 National Pavement Expo, GemSeal’s Lee Lowis explained that asphalt pavement offers poor resistance to ultraviolet radiation and sunlight. He said that exposure to sunlight results in oxidation of the pavement, which results in a loss of pavement “plasticity.” Lowis said oxidation allows the attraction of water molecules, which accelerates thermal and fatigue cracking and surface raveling.

So the reasons to sealcoat are directly related to what sealcoating can do to address each of these issues.

Assuming that most asphalt pavements are designed and constructed correctly – meaning the subgrade is sound and compacted, the appropriate base material is placed and compacted properly, and the correct thickness of hot mix (based on type and volume of traffic) is placed and compacted properly – sealcoating will extend pavement life by protecting the asphalt binder from oxidation, slowing the inevitable deterioration.

“Sealer is only as good as the bituminous pavement to which it is applied,” according to the Neal Mfg. Total Maintenance Handbook. “It will not prevent the cracking of bituminous pavements caused by excessive voids, poor mix stability, poor compaction or low use areas.”
Slowing oxidation

Because asphalt pavement offers poor resistance to UV rays and sunlight, it begins to deteriorate as a result of oxidation – exposure to the air and sun – as soon as it’s constructed.

Oxidation deteriorates asphalt – the binder in asphalt pavement – quickly,” Vance says. “Oxidation speeds up the aging of asphalt pavement, so anything you can do to slow the oxidation process will extend pavement life,” Vance says. “Sealcoating will slow oxidation.”

“When you put that asphalt pavement down it’s loaded up with oils, and you need some of that oil to oxidize out, which strengthens the pavement. As the oils leave, the asphalt gets harder and harder,” Luzar says. “But if you allow too much of the oils to oxidize out the pavement becomes brittle and more susceptible to cracking. So you need to sealcoat before that happens.”

As oxidation progresses, fines are released from the pavement surface, exposing larger aggregate, and as the pavement continues to dry out and is exposed to traffic (as well as a variety of weather conditions) aggregate can be pulled out of the pavement and small cracks begin to form. These cracks, if left untreated, eventually become larger, providing a way for water to work its way beneath the pavement.

“Once you get even one crack in there you’re going to get water in the subgrade and that water starts creating mini sinkholes,” Luzar says. “As traffic drives over that part of the pavement the soft subgrade makes it easier for the pavement to crack, and pretty soon you have alligatored areas that can only be fixed through remove-and-replace.”

He says sealcoating protects the asphalt surface by slowing oxidation and by filling the hairline cracks that eventually can become entryways for water. It also (because sealer contains fillers and usually sand) replaces some of the fines lost through oxidation and erosion and fills hairline cracks.

“If left unprotected, the asphalt binder, or glue that hold the stone and sand in place, loses strength and the mat becomes brittle, allowing stone and sand to roll out,” Houser says. “The surface will crack, allowing water to get in, creating alligatored areas, potholes and other defects.”
Sealcoating as Part of a System

“Keep in mind it’s a film we’re putting on there. I worry that sometimes people oversell it too much,” Vance says. “It’s a good practice and a smart practice to sealcoat a parking lot, but there are limits to what it can do,” Vance says.

For example, sealcoating doesn’t stop water from coming in. “Water will find a way into the pavement if the pavement hasn’t been built properly. Water always finds the path of least resistance,” Vance says.

Which is why Luzar and Vance say sealcoating needs to be done in conjunction with other pavement maintenance practices, specifically cracksealing and remove-and-replace pavement repairs.

“It needs to be part of a system,” Vance says. “If you have a damaged area or a pothole, that needs to be removed and replaced before sealcoating for sealcoating to be most effective. And cracks need to be filled properly because sealcoating isn’t designed as a crackfiller.”
Improving Pavement Appearance

There’s no question that sealcoating improves the appearance of asphalt pavement, and in fact appearance is one reason many property managers sealcoat their pavement every year or two.

The parking lot is the welcome mat to your property – to your store or your mall,” Luzar says. “So if your parking lot looks terrible then you don’t present an inviting place and that’s going to affect your store traffic. On the other hand if it’s nice and black with bright stripes – that tells the public that you run a nice operation and you take care of the place they’re going to visit, so you’ll probably take good care of them.”

The Institute of Real Estate Management (IREM) confirms that the subjective idea of “curb appeal,” or how a property looks to the public, is in fact a very real phenomenon. Houser says that on a scale of 10, appearance ranks 8 and the parking lot is a big part of that perception. So one of the simplest things to improve a property and raise its “curb appeal” is to sealcoat the parking lot.

“One of the most important ways to attract and retain tenants in office building or property management settings is to maintain the property's exterior and curb appeal,” Houser says. “The property’s parking lot is the first impression for potential tenants and their customers, so curb appeal is paramount. A clean, well-maintained parking lot indicates a professional outlook in all aspects of business and translates into a positive first impression.”

Refined coal tar sealer is a blacker product that many property managers prefer, but asphalt-based sealers also result in an improved pavement appearance, making striping stand out and improving the curb appeal of property.

“Aesthetically, sealcoating shows off the grass, the stripes and the building making it all look better and more appealing,” Vance says. “We’re a service-oriented society and an ego-centric society and we all like to look good. So anything property owners can do to improve the appearance of their parking lot makes their shopping center or mall or office building that much more appealing to the public.”

“Sealcoating does make a pavement look great and that’s important to a lot of property owners and managers,” Luzar says. “But the main reason for sealcoating is to keep the fines and the aggregate locked into the asphalt so the pavement doesn’t crack. Sealcoating locks the fines and binder and aggregate into the asphalt.”
Which Type of Sealer?

Because of its petroleum-based nature, asphalt pavement offers poor resistance to petroleum products, chemicals and salts. Gasoline and oils dissolve directly into the asphalt and the petroleum products soften the pavement structure. So simply because of its chemical makeup refined tar sealer offers better protection than asphalt-based sealers against gasoline, oil, chemicals and salt.

Refined tar sealers generally last a year or so longer than asphalt-based sealers. But he says most sealer producers make both type of sealer (in addition to asphalt-refined tar blends) so the decision on which type of sealer to use is often dictated by contractor preference and market demand.

“Whether you use an asphalt-based sealer or a refined tar sealer as long as you’ve done something you’re money ahead".

 “Sealcoating and other pavement maintenance techniques add value and extend the life of existing pavement, making the use of sealer a cost-effective approach to pavement maintenance.”





Asphalt Maintenance & Repair: 5 Do's and Don'ts

Asphalt maintenance and repair is a lot more than repaving. In fact, repaving is usually going to be your last resort. There are a number of things you can do (and not do) to extend the life of your asphalt pavement. But the most important part of maintenance is being proactive: you've got to keep your good pavement good. This means treating your pavement before any serious deterioration starts.

Below are five DO's and DON'Ts for asphalt maintenance and repair. 

 1) DON'T allow your asphalt to become oxidized (Grayed out)

Oxidation occurs when your asphalt is exposed to oxygen and the sun's UV rays without any protection. The binder (or glue) that holds together your asphalt (which is made of aggregates and sand) breaks down causing raveling on your surface. Oxidized asphalt is also brittle, and it becomes more prone to cracking.

You'll be able to tell when your asphalt is oxidized because it will have a gray color versus a dark black color that new asphalt has.

2) DON'T let sprinklers direct water onto your asphalt

If you have sprinklers near your parking lot, make sure that they don't direct water onto your asphalt. Water is one of the top reasons for pavement degradation. If water penetrates into your pavement, it softens the base course which can cause depressions in your pavement and ultimately lead to potholes (which will then allow even more water into your pavement).

3) DON'T allow heavy loading on your asphalt

Extremely heavy vehicles, such as garbage trucks, put an enormous amount of stress on your pavement. If your asphalt pavement already has cracks or a damaged base course, the stress of the heavy vehicle will only deteriorate the pavement more.

If you have to have heavy vehicles on your asphalt, consider installing a concrete pad where these heavy vehicles frequent. Such as garbage trucks.

4) DON'T neglect pavement maintenance

When it comes to asphalt, small issues turn into larger ones quickly. If you don't protect your asphalt, it will become oxidized, which will lead to cracks. Cracks allow water into your base course, and when your base course's integrity is compromised, you end up with depressions in the pavement and potholes. However, if you address cracks and other issues in a timely manner, you can prevent your asphalt from degrading to that point. Common pavement maintenance tasks are: sealcoat, crack fill, oil stain removal, pothole repair, and Striping and marking.

5) DON'T always pick the bid with the lowest price

When it comes to finding a contractor to perform the work, whether it be sealcoating, crack filling, pothole repair, etc., you may be fixated on the lowest price. However, it's important to make sure you're comparing apples to apples, and not apples to oranges.

Two bids may vary in price because the scope of work may be different for each bid. Read our "DO" to learn why.


Now, onto the "Do's":

1) DO sweep your asphalt pavement at least once a year

Sweeping your asphalt removes loose gravel from your surface, improving its appearance. It also allows you to inspect your asphalt for cracks and depressions that could indicate early pavement degradation. The sooner you can catch signs of degradation, the sooner you can take preventative actions such as crack fillingand sealcoat.

2) DO sealcoat your asphalt every three to five years

A sealcoat acts as a barrier that protects your asphalt's surface from oxidation and water penetration. It's like sunscreen. Just as sunscreen is used to protect your skin, a sealcoat protects your asphalt surface. But like sunscreen, a sealcoat needs to be reapplied! For most situations, you should be OK if you sealcoat your asphalt once every three to five years. You may need to do it sooner if your parking lot experiences heavy/constant traffic.

3) DO crack fill as soon as possible

Cracks allow water to penetrate into your pavement and degrade your base course. Once you've got a base course failure, you'll get more cracks in your pavement which will lead to alligatoring and potholes. Therefore, it's very important to prevent water penetration, and filling cracks in a timely manner is imperative. 

4) DO plan to repair potholes even if you've used a pothole patching material

Most off-the-shelf pothole patching materials deteriorate quickly. In these cases, you may need to go back and repair/re-patch the same pothole again in a month or two. Our pothole repair material, provides you with longer relief (about a year), but in the end, you still will need to actually fix the pothole. Remember, a pothole forms because the base course is damaged. Using a patch fills the hole to prevent more water penetration, but it does not fix the damaged base course. When we say "fix" the pothole, we mean cut out the damaged area and pour new asphalt and re-compact. 

5) DO specify job scope when soliciting bids

If you ask for pricing from two different contractors without a scope of work, you could get two wildly different prices. For example, Contractor A may provide a price for just sealcoating while Contractor B may provide a price for crack fill, pothole repair, and sealcoating. Of course Contractor A will have the lower price, but Contractor B may provide a more complete pavement maintenance plan.

You need to consider what needs to be done. Some areas of your asphalt may be so far gone that you need to repave (in which sealcoating the area is a waste of money). Another area may just need a sealcoat while a third area may need cracks to be filled before sealcoating. With so much variables, this is why it's so important to have your asphalt inspected and to come up with a scope of work before soliciting bids.