Asphalt Parking Lot vs. Concrete Parking Lot: What to Know

May 13, 2018

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Installing a new parking lot in a commercial building may be an expensive investment, but a new parking lot surface can protect vehicles from damage due to potholes and chipped or cracked pavement. A new parking lot surface will also be safer for pedestrians, reducing your risk of a slip-and-fall liability lawsuit!

Fresh concrete or asphalt may also provide a better surface for paint and stencils so that traffic and parking lines are more visible. When having your new concrete or asphalt parking lot installed, you also have the opportunity to rethink the size and structure of the current lot, so you can add or remove spaces, widen traffic lanes, and even add a bike path!

When having a new parking lot installed, you will typically need to decide on the paving material itself. Asphalt and concrete are the two most common materials used today, and both offer their pros and cons for larger parking lots. To help you make the best decision when it comes to your new lot, note some necessary information about both asphalt and concrete, along with a few of those pros and cons of these materials.

Asphalt vs. concrete terms to learn

First, consider a few basic terms to learn when choosing between concrete and asphalt. Knowing these terms will make it easier for you to understand your choice of paving materials.

• Cement, which many people confuse with concrete, is a binder or paste. This binder is part of the mixture that makes concrete.
• Cement is made from crushing and burning rocks and gravel that have a high concentration of clay and carbonate. When these minerals are heated, they become very sticky and then act as a binder for other materials.
• An aggregate is a material added to asphalt or concrete, to make it bumpier and to give the substance texture and strength. Most aggregates are formed from pebbles, gravel, and smooth glass, and they may also contain a mixture of sand and other similar materials.
• Aggregates may be broken up before being added to an asphalt or concrete mix, so the stones are large enough to add strength to the mixture but small enough to be compacted and rolled. This compaction provides asphalt or concrete with a textured but somewhat smooth surface that is safe for driving and walking.
• A layer of aggregates is also poured onto the ground that will be paved with asphalt or concrete, to provide a solid foundation for these materials, and to protect both asphalt and concrete from being exposed to frost. This layer of aggregate is called the material's sub base.
• Some aggregates are also added to the top layer of concrete or asphalt, to create texture. This texture provides added traction for vehicles and foot traffic, and may even help slow down water drainage on very dry properties. Aggregates like smooth glass or colored pebbles might be added to residential driveways, for decoration or to create a specific design in the concrete's surface.
• Seal coating refers to a process of adding a protective layer of sealant over a concrete or asphalt surface. This sealant is typically added to a paving material after installation, and seal coating may then need to be done regularly over the years. Seal coating will protect both concrete and asphalt from stains and discoloration, as well as cracks, chips, potholes, and other damage.
• Spalling refers to damage you might see on the surface of concrete, where the material appears to be peeling away. This spalling is also sometimes called concrete cancer, and it should be addressed quickly, to keep concrete strong and durable and to help avoid potholes and cracks.
• Expansion joints are small trenches between sections of concrete. These gaps give concrete room for it to expand as it absorbs water. In turn, the material is less likely to buckle and crack as it goes through this swelling and then drying cycle.
• Butt joints are added to an area of asphalt that connects to another surface material. These butt joints are typically sloped just slightly so that there is a smooth transition between the pavement and a connecting walkway, roadway, and the like.

How is asphalt made?

Asphalt, sometimes called bitumen, is made from a distillation of petroleum. This distillation process creates a tar-like substance from crude oil, called pitch. Pitch is then mixed with aggregates to make asphalt.

Each batch of asphalt is made to specific specifications, so that these batches can have different types of aggregates added, in different ratios. For example, the asphalt used for a home driveway might have a higher concentration of sand than gravel. This added sand offers a smoother and lighter surface that homeowners often prefer.

However, a public road or commercial parking lot may need asphalt that has a higher mixture of gravel, and the pebbles or rocks used for the aggregate may be bigger than average. Larger aggregate will make the asphalt bumpier, for added traction, as mentioned. Larger aggregate also makes asphalt stronger, so that it can more readily withstand the weight of heavy vehicles.

The mixture of asphalt and the aggregate added may also affect the materials' density. A more porous asphalt will allow more water to drain away rather than collect on the surface of the pavement. This porous material can be a good choice in rainy or snowy areas.

How is asphalt installed?

Before any paving material is installed, the ground may need to be torn up. This clearing is to create a "clean slate" for the paving material so that weeds and other vegetation don't grow under the concrete or asphalt you'll have poured, pushing against it, causing cracks. The ground may also need to be graded, for proper water runoff.

The sub base, or a layer of aggregate, is then added, to create that firm and stable foundation for your paving material. The sub base may be pressed or crushed so that it's compacted and firm, and less likely to shift and settle over the years.

For asphalt installation, a binder layer is typically poured over this sub base. This binder layer is made of a mixture of aggregate and oil, so that it's stable and durable, and is meant to help keep the top layer of asphalt firmly in place.

Surface asphalt is added over this binder layer and is rolled or pressed into place. This rolling process allows all those layers of material to bind together, creating a solid surface. Once the asphalt cools and solidifies, it's then ready for use.

How is concrete made?

Concrete is a simple mixture of water, cement, and aggregates. As the cement in this mixture dries, the material hardens and creates concrete. Concrete dries relatively quickly, which is why trucks keep their drums or mixers turning when concrete is about to be poured, to keep this mixture from drying and hardening too soon.

As with asphalt, the mixture or proportioning of concrete batches can vary, according to the density needed for the material. A mix with more water will mean more gaps between each piece of aggregate, for a more porous surface. While this type of concrete may allow for more water to drain away from that surface, it will also be weaker and not able to bear much weight.

On the other hand, concrete with less water added to the mix will be denser. While this makes concrete stronger, a mixture that is too dense may become brittle and will be more likely to crack and chip.

How is concrete installed?

There may be more steps and details to pouring concrete than you realize, as the mixture can be very heavy and runny, and is also affected by the weather when it's poured!

• As with asphalt, the first step to pouring concrete is to prepare the ground; this can include clearing the land and then rolling it so that it's stable and firm.
• Forms are put into place where the concrete will be poured so that the material stays within that area while it dries. Setting up forms also allows for a smoother pouring of concrete, so that bubbles and honeycombs don't form along its surface. Concrete forms are typically very inexpensive, thick pieces of wood, nestled into the ground around the area of installation.
• A sub base is then added, and it may be crushed and rolled into position. This process ensures that the aggregate used for this base is made of small enough pieces, and is compacted enough, to support the weight of the poured concrete, and of vehicle traffic.
• For larger installation jobs, rebar is often added between those forms, and the concrete is poured right over these spans of metal. This rebar adds support to the pavement and keeps it from cracking or chipping, and especially when the concrete needs to support heavy vehicles.
• As concrete is poured inside those forms, it is compacted or consolidated. You may see concrete installers do this by running large, flat tools over its surface. This compaction keeps the surface of the concrete level and even, and eliminates air bubbles.
• The concrete is also leveled with the use of large, flat boards dragged across its surface. Not only does this give concrete a smooth surface, but this leveling also pushes the aggregate of the concrete into the mixture, so the pavement becomes very dense and hard.
• Expansion joints are formed, and the concrete might be groomed, meaning a brush is dragged across the top, for texture. For residential concrete, a decorative aggregate might be added, for more color and style and to give the pavement less of an industrial look.

After these steps are completed, the concrete is cured. Curing concrete is a type of controlled drying process; you allow concrete to absorb moisture from the air while controlling the hydration the material loses as it dries. Controlling the moisture levels of concrete helps to control the overall strength of the finished pavement; the more moisture the concrete retains while it sets, the stronger it will be once it solidifies.

Curing concrete might be done by adding a type of water fog or mist over the surface of the material before it dries, and covering the material with heavy cotton or burlap cloth. This covering helps to keep moisture in the mix while also allowing the concrete to dry gradually.

Asphalt vs. concrete installation costs

Concrete is almost always more expensive to install than asphalt, mostly because it's more labor intensive to pour and level concrete than asphalt. This cost can be an essential consideration for the owner of a large commercial parking lot, and especially if you're going to expand that lot before having your new paving material installed.

You can reduce the cost of concrete by reducing the thickness of the material, and choose the thinnest layer that is allowed according to local building or construction codes. A thinner layer of concrete, however, might not be able to support heavy vehicle traffic, so be cautious about having a thin layer of concrete poured if your parking lot will need to withstand delivery trucks, cargo vans, and other such vehicles.

Asphalt vs. concrete repair costs

While the cost of installation for concrete may be higher than that of asphalt, note that concrete might last twice as long as asphalt lot before the material needs replacement. Consider your long-term repair and replacement costs when deciding between the two, and not just the cost of installation.

Asphalt can also be resurfaced more readily than concrete, meaning that you can add a new layer of material over the old when your parking lot is severely damaged. This resurfacing produces a thicker layer of asphalt that is stronger against heavier vehicles, while also filling in cracks and other such damage. In turn, even a severely damaged parking lot can be given an entirely new surface for a fraction of the cost of having a new lot installed.

Repairing cracks in asphalt between resurfacing or repaving is also faster and more affordable than repairing concrete. Asphalt patching kits are very affordable and can be applied by virtually anyone, keeping the asphalt surface strong and in good repair.

Maintaining concrete is often more difficult and expensive; if the surface has developed a crack that splits the pavement, or if there is a hole that goes through the concrete itself, you'll need to buy fresh concrete for this patch job. The crack or pothole will need to be cleaned out thoroughly or even outright removed. The area is then filled with new concrete, and allowed to set or cure.

Note, too, that an area of patched concrete is often apparent and noticeable, and especially if the original concrete is painted or stained. Asphalt patching, however, blends more readily with the original material, so even patched asphalt may look like new.

When it comes to overall costs of asphalt vs. concrete, one last factor to consider is that the cost of crude oil may affect the cost of asphalt. Since asphalt is made from petroleum, when crude oil prices go up, the cost of asphalt may also go up.

This price fluctuation can affect your installation costs, as well as any repair or resurfacing costs. The materials that make concrete, however, such as sand and gravel, typically don't fluctuate so rapidly, so your repair and replacement costs for concrete may be more consistent over the years.

Environmental factors for asphalt versus concrete

When deciding between asphalt versus concrete, you might consider some environmental factors for your local area. These factors can help you choose the right material for your commercial parking lot.

Note that the darker color of asphalt might cause it to hold more heat than concrete. This added heat can be useful in areas with heavy snowfall, as it can help to melt snow and ice. You may then need to use less salt, and send the snowplows over your parking lot less often when you choose asphalt! Salt in wintertime can also cause pits and pores to form on the concrete and can cause concrete cancer, where the top layer begins to peel away from the concrete itself.

The bumpier texture of asphalt can also mean more traction, as said, which is an excellent choice when you live in an area with lots of snow and ice, or with heavy rainfall. This traction can be especially necessary for commercial parking lots that see lots of heavy trucks and delivery vehicles that may already have less stopping power due to their weight.

Bitter cold can also make concrete brittle and more prone to cracking and breaking. The softer material of asphalt allows it to expand and shrink more easily in extreme temperatures, so it's less likely to crack during winter.

If your commercial facility is located in an area with lots of bright, direct sunlight, the darker color of asphalt can also cut down on glare for drivers. Painted parking and traffic lines and stencils also show up better against that darker color, something to consider if your facility is open at night.

On the other hand, hot temperatures and direct sunlight can make asphalt softer. Turning a vehicle's wheels while it's immobile on soft asphalt can cause indentations and swirl marks in the material, which can lead to water damage and potholes in the pavement that will soon need expensive patching and repair.

Asphalt might also retain heat during the summertime so that it's outright dangerous for walking. This hot surface might not be an issue for many commercial facilities, but consider the parking lot outside a veterinarian's office or pet clinic, where animals may be walking on that hot pavement. A lighter-colored concrete can be a better option in those cases.

The softer and more porous surface of asphalt also allows the material to absorb more sound waves. If your parking lot is host to big delivery vehicles, or if your commercial facility is located near a busy roadway, consider asphalt for the sound absorption it offers. Traffic and other such noises may not be silenced, but they will be more muffled when you pave your lot with asphalt, versus concrete.

The softer and more porous material of asphalt also absorbs vibrations from heavy traffic. If you have a building with windows that tend to rattle every time a large truck goes by, or if your business is located near production facilities that use heavy machinery, asphalt might absorb the vibrations from that machinery. In turn, you won't notice those vibrations underfoot, and they won't interfere with any delicate equipment you may use at your business.

The appearance of asphalt versus concrete

When you're ready to have a new parking lot poured, you may not think much of the appearance of the material you'll choose, but curb appeal can affect the property values of a commercial building as much as a residential home! The darker color of asphalt can provide a nice contrast against a white commercial building, and adding more to the asphalt mix can lighten its color so that it works well against a darker structure.

Note, too, that the darker color of asphalt may hide stains and discoloration better than light concrete. This camouflage can be necessary for a commercial lot, where vehicles may continuously drip oil and other fluids, and visitors may toss out soda and other such trash that can discolor a parking lot's surface.

The lighter color of concrete, on the other hand, may look better against a dark building. Concrete can also be painted. This paint may need consistent touchups in a commercial parking lot, but it can make your lot look coordinated with your building. You can even paint a parking lot your company colors or add your logo in the middle of the lot, provided this is allowed by local construction codes.

Asphalt vs. concrete environmentally friendly factors

Many business owners today are looking to make environmentally-friendly decisions wherever possible. These decisions include recycling their materials, cutting down on packaging waste, using less plastic, and so on. In some cases, this choice is for marketing reasons, so they can assure their customers that they're making responsible choices, but other business owners may be genuinely concerned about how their decisions impact the environment.

• One thing to note about concrete is that it is made from raw materials that are often easy to source locally. Sand, gravel, and the other elements that make cement are typically found in abundance in just about any area, or are quick to deliver from a nearby location. Sand and gravel are also easy to harvest, with little disruption to the environment.
• The petroleum used to make asphalt, however, may not be so abundant, and may not be locally sourced. Choosing asphalt can then mean more fumes and emissions from the delivery trucks needed to get those materials to your local production facility. Petroleum extraction can also be upsetting to the environment, as it involves drilling into the earth and breaking through rocks and other natural formations.
• Concrete and asphalt are both recyclable. Older asphalt can be broken into smaller pieces and then sent through a crusher, to create half-inch size chunks that are then added to new batches of asphalt. The heat used to keep the petroleum in asphalt pliable helps to break down these older chunks, so they get mixed in with the new pavement as it's made.
• Reclaimed concrete can be crushed and then used as a sub base for new paving materials. It can also be added to new concrete batches when needed, to reduce the amount of virgin materials that are harvested and then trucked in from other locations.

Since both concrete and asphalt are recyclable, which one is the best choice for the environment? There is no easy answer to this question, as both materials are very eco-friendly.

Concrete, including recycled concrete, is in high demand since painted and stained concrete is being used more and more for kitchen countertops and indoor flooring in residential homes. Broken pieces of old concrete can even be used by homeowners in place of patio pavers, or for outdoor fire pits, retaining walls, and flowerbeds.

On the other hand, there is a significant amount of asphalt that is used for public roadways today, since the new material sets faster than concrete, and roads can open sooner when asphalt is poured. The textured surface of asphalt also means better traction for vehicle traffic. In turn, recycled asphalt is also in high demand, to reduce the cost of producing the raw material needed for such projects.

When it comes to environmental factors, you might take into account other considerations. For example, if your commercial parking lot is in an area with lots of snowfall, that warm surface of asphalt may mean less salt is needed for clearing your lot; in turn, there will be less salt that winds up in the soil and drainage canals. Less snow and ice clearance also means fewer emissions from salt trucks and plows every winter!

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