Asphalt is a favorite paving material for commercial property owners and homeowners, as it is affordable to install and cures rather quickly, so it's available for vehicle traffic soon after it's been poured. Asphalt is also extremely durable, but it does need some maintenance over the years, to keep it from chipping and developing potholes and to repair minor damage that might develop along its surface.
Asphalt needs routine repair from damage due to motor oils and other petroleum-based fluids and requires consistent seal coating to keep it in good repair. Patching potholes and chips will also keep the material durable and stable, and in excellent condition for many years.
To better understand how to maintain asphalt, it's good to know some basics about how this material is composed. You might also appreciate knowing some benefits of asphalt especially as compared to concrete, so you know why this is a favorite paving material for commercial as well as residential properties, despite any maintenance it might need over the years!
What is asphalt?
Knowing some basics about the composition of asphalt used as a paving material can help you to understand better why and how it gets damaged. In turn, you'll then know how to protect and repair this material, as said.
Asphalt is a semi-solid form of petroleum. This petroleum substance is mixed with rocks, sand, and aggregates, as well as a binder, called asphalt cement, to create asphalt used for paving. This binder or cement gives asphalt its stickiness, while the aggregate and rocks add texture. Sand is added to adjust the overall thickness and consistency of the finished asphalt.
The terms "asphalt," "blacktop," and "bitumen" are somewhat interchangeable. However, the word bitumen is used far less often than asphalt and technically refers to the substance that binds asphalt paving together. Blacktop also typically applies to a residential driveway or small lot, such as a basketball court, paved with asphalt. Some types of tar, such as those used for roofing, are a form of asphalt, although they are usually much thinner and far less bumpy in texture.
How is asphalt installed?
A contractor doesn't merely pour and spread asphalt, as is done with concrete. Instead, he or she will first clear the surface to be paved, as necessary, and the area is then compacted so that it can provide a solid foundation for the asphalt paving material.
A thin layer of asphalt binder is then applied or sprayed over the compacted surface. This layer of binder allows the asphalt to adhere better to the surface under it, and also provides more protection against water seeping in underneath the pavement.
The binder is then covered in asphalt, and the mixture is pressed and rolled into place. This rolling makes the asphalt compact and firm and helps the upper layer of asphalt to attach correctly to the binder underneath it. This top layer then needs time to cure and set and is then ready for striping and vehicle traffic.
Is asphalt all the same?
Homeowners and commercial property owners often don't realize that not all asphalt is the same. While this paving material uses the same basic mixture of contents for all applications, the amount and ratio of those materials can vary. More sand can make the asphalt thinner; a thin, sandy mixture may be cheaper to install and more suited for residential driveways or small commercial lots.
A higher ratio of aggregate can make asphalt bumpier. A bumpier surface provides more traction and is suitable for areas with lots of rainfall, snow, and ice. Public roads and commercial parking lots are often paved with asphalt that has a higher concentration of aggregate, to reduce vehicle skidding and also slip and fall accidents.
How long does an asphalt driveway last?
An asphalt driveway will typically last anywhere from 12 to 20 years, depending on the quality of the installation, the material used to create that asphalt, your everyday climate, and the traffic to which the pavement is exposed. The better care you take of that driveway, the longer it will last between repairs, and the less often you'll need to have the asphalt replaced.
Note, too, that it's often possible to add a new layer of asphalt over an existing layer, rather than always having to remove or tear-out the old material. Whether or not this is an option for your property will depend on the thickness of the original asphalt installed and its overall condition, as this original asphalt does need to be strong enough to provide a stable base for new material. However, if you can avoid a tear-out, this can make the installation of new asphalt faster, more affordable, and even more eco-friendly, as you don't need to worry about recycling or disposing of that old asphalt!
How do I protect my asphalt driveway?
To protect your asphalt driveway, parking lot, or other such surfaces from everyday damage and excessive wear and tear, you might appreciate knowing the most common enemies of asphalt and how to fight them off! Note how and why asphalt gets damaged:
- Direct sunlight is very drying to the binder that holds asphalt together and can cause that binder to break down and lose its adhesion. When this binder dries and then breaks down, you will see lots of loose gravel and sand on the surface of asphalt.
- Oxidation, or long-term exposure to oxygen, and standing water on the pavement's surface will also cause an asphalt binder to break down. Chips, cracks, and potholes then form in the asphalt.
- Heavy vehicles can put undue pressure and stress on asphalt binders and cause the materials to separate. When this happens, you may notice deep grooves in asphalt that indicate traffic lines and may also see specific areas of pavement that start to crack and appear very thin.
- Oil stains are one of the biggest culprits when it comes to damaged asphalt! The petroleum in motor oil breaks down the petroleum base of asphalt pavement, causing the binder to become unstable. Motor oil spills are one reason why many potholes form in parking lots at the front of parking spaces, where you're most likely to see oil drips and leaks from vehicles.
Asphalt maintenance tips
Now that you know a bit more about the construction of asphalt, note a few maintenance tips that any property owner can use:
- Power wash your asphalt regularly. Regular power washing will remove damaging oil stains, snow clearing salt, pesticides, fertilizers, residue from acid rain, and other corrosive residues. A healthy dose of water will also reverse the effects of oxidation for pavement that is rarely covered and always exposed to the surrounding air, while power washing removes standing water and puddles from that pavement.
- Fill in potholes immediately. Inspect your driveway or commercial lot on a regular basis and fill in potholes right away, rather than ignoring them. Neglecting potholes allows them to get larger and then collect standing water and other damaging debris. Standing or pooling water and corrosive residue will damage the lower layers of asphalt and cause the material to get soft and then crack and chip.
- Sealcoat the asphalt on a regular basis, as recommended by the manufacturer or installer and according to your local environment and everyday use of that asphalt. Seal coating fills in minor surface damage and also provides a layer of protection over the top of your asphalt pavement.
It's also good to note how you treat the asphalt in a parking lot or driveway, as this can help to keep that pavement in excellent condition. As an example, be sure to avoid scraping the blade of a snow blower along the surface of asphalt, so that you don't loosen any aggregate or make small chips and cracks much larger.
If you need to create parking space lines and markings or want to add a decorative element to a residential driveway, be sure to use paints manufactured for asphalt in particular. Using an incorrect type of paint can cause corrosion to that asphalt surface and might then lead to chipping, cracking, and other such damage.
Grade your property so that water runs away from a driveway, or will drain off a commercial lot easily. A landscaping engineer can note the grade of your property and then design trenches or other such drainage features, to keep the asphalt clear of damaging water buildup.
If you do notice indentations in your commercial lot or driveway at home, this might indicate that the asphalt mixture is too soft or that the asphalt itself is too thin for its everyday use. A new layer of asphalt might be needed so that it's strong enough and thick enough to withstand heavier vehicles, your area's average weather conditions, or the amount of traffic to which it's exposed every day.
How to repair asphalt driveway
Huge potholes or broken chunks of asphalt should be repaired by a professional, so the job gets done right, and the asphalt lasts as long as possible. However, for smaller potholes, cracks, and other such minor damage, note a few tips on how to address this damage on your own.
- Start by completing cleaning out the pothole or crack. Use a wire brush meant for pavement cleaning or rust removal, and then pressure wash the opening, to get out all debris.
- Allow the area to dry completely before adding any filler or patching material.
- If the pothole or crack is larger than a small hairline, or if you can see the ground under the asphalt, add perhaps 1/4" or 1/2" of sand.
- Tamp the area down to create a firm foundation for new asphalt.
- Add premixed filler material, available from most hardware or home improvement stores. Tamp this material down as you add it so that it's compacted and also level and even with the existing asphalt.
- Allow the filler to dry according to its package directions, usually for 24 hours. You'll then want to add a coat of sealer over the area and allow that to dry as well.
What are the benefits of asphalt over concrete?
Both asphalt and concrete have their pros and cons, but note some benefits of asphalt versus concrete in particular. This information will help you to determine if asphalt is the right choice of paving material for your property!
- Concrete takes several days, if not even weeks, to properly cure and set, and before you can introduce it to vehicle traffic. A vandal or animals can also make marks in wet concrete during this dry time, so the pavement is then permanently damaged. Asphalt, however, often only needs a few hours to set and cure, so you can typically open a parking lot or start using a residential driveway the same day or the very next day after installation.
- The soft, porous nature of asphalt allows it to absorb sound waves, creating a quieter exterior environment. This added sound insulation can be especially important to consider for office buildings or residential homes located near busy roadways or other such distractions. The more sound absorption you can provide outside your structure, the more comfortable the interior space!
- Asphalt is often much cheaper than concrete to install. This cost can be significant for businesses with large parking lots, or for a homeowner with a long driveway that needs repaving.
- The dark color and rough surface of asphalt make it safer in winter months, where it may more readily melt snow and ice and provide better traction for vehicles and foot traffic. This feature can also be useful for basketball courts or other such surfaces that involve lots of foot traffic, as the added texture of asphalt can mean less slipping and sliding.
- The dark color of asphalt also provides a nice contrast against white buildings and may reduce glare during daytime driving. Parking and driving lines may also be more visible against the black surface of asphalt, allowing for safer driving and traffic even at night.