Why Are Roads Made of Asphalt and Not Concrete?

Published Categorized as Infrastructure
Asphalt Road

The two most common types of roads that you will likely come across are asphalt and concrete. However, you will probably drive on asphalt roads much more frequently as asphalt is preferred over concrete. But why is asphalt used for roads rather than concrete?

Roads are made from asphalt and not concrete because asphalt is cheaper to install and maintain. The time needed to install asphalt is considerably less than concrete. Asphalt roads provide a safer driving surface with more grip as well. Asphalt is also 100% recyclable, unlike concrete.

Keep reading to learn more in detail about why roads are made of asphalt, when concrete is required for a road, the costs involved in maintaining both materials, and the safety properties of asphalt.

Why is Asphalt Cheaper Than Concrete to Install?

Asphalt roads are significantly cheaper to install than concrete roads. This is one of the main reasons for asphalt’s popularity. There are a few factors as to why asphalt is so much more affordable than concrete to install.

As a raw material, asphalt is significantly cheaper than concrete. Asphalt costs roughly $2-$4 per square foot for materials, whereas concrete costs $4-$8 per square foot. That’s double the cost of asphalt to purchase the raw materials.

Quick, efficient installation is why asphalt is cheaper than concrete. This reduces delays caused by roadwork and means less money paid for labor. The cost of delivery equals a couple of dollars per square foot. Concrete, however, takes much longer to install, which means higher labor expenses.

Using concrete on roads would result in drawn-out roadworks disrupting traffic for much longer than they are needed. The more extended period required for concrete installation also results in much higher labor expenses. This, in turn, drives up the cost of the building of concrete roads. 

Concrete roads often require rebar to reinforce the structure. Rebar is made using steel or iron, which can quickly become very expensive. On top of this, concrete often requires a finish to protect it against the elements. This also adds to the cost of installing concrete.

Concrete is between two to three times more expensive than asphalt to install after you take all of the added costs into consideration.

Why is Asphalt Safer Than Concrete?

When it comes to selecting a material for roads, safety should be a top priority. Studies estimate that over 1.25 million lives are lost every year on the streets worldwide, with experts expecting road accidents to climb to the fifth most common cause of death by 2030.

One major factor contributing to accidents on the road is the road surface itself. Vehicles often skid and slide when they lose friction while traveling at speed. Potholes and cracks can also cause drivers to lose control and crash.

Asphalt is considered a safer driving surface than concrete. One of the main reasons for this is the absorbent and porous nature of the asphalt. This allows water, oil, and vehicle fluids to seep into the material rather than sit on the surface.

Concrete roads do not allow for liquids to pass through freely, which results in spills staying on the surface for a more extended period. These spills can cause a vehicle’s tires to lose grip with the road surface, which can quickly render a severe accident.

Asphalt roads are also smooth and uniform. This allows for drivers to seamlessly coast along without having to worry about bumps and holes. Smooth driving surfaces provide drivers with a safer and more convenient driving experience.

Another key safety feature of asphalt roads is the skid resistance properties of asphalt. Asphalt provides superior grips for drives than concrete as a result. This reduces the risk of vehicles losing control or traction while in motion.

In addition, asphalt roads also provide more contrast in color between road markings and the road itself than concrete. Asphalt is black, while road markings are usually yellow, white, or blue. This provides a clear contrast which results in more visible road markings regardless of the light and weather conditions.

Why is Asphalt Quick to Install?

Asphalt is quick and convenient for roads, especially compared to other building materials such as concrete. Here are several reasons why asphalt is much quicker to install than concrete.

The main reason why concrete takes longer to install is the structural support that concrete requires to remain strong and durable. Concrete roads need rebar or galvanized mesh cages to ensure that the road binds together effectively. As a result, concrete requires a rebar to be laid out before the concrete can be poured. This results in a longer installation process.

Asphalt doesn’t require structural support to remain in place and shape, therefore, it takes less time to install when compared to concrete. It is applied evenly to a surface when hot. It then cools down and sets quickly, producing a smooth and durable driving surface. Concrete takes longer to dry.

The process of installing asphalt takes only a few hours to complete even a large road section, making asphalt the most common choice for busy streets. Disruptions caused by installing new roads, as well as labor costs, can be minimized by choosing asphalt over concrete.

The difference in the time it takes to install asphalt and concrete results in a difference in cost. Longer installation times result in higher labor fees, which drives up the cost of installing a new road. Also, road disruptions can cost local economies money as business may be disrupted, so speedy installation is a massive benefit for asphalt.

Asphalt takes less time to dry and settle after it has been laid, whereas concrete can take up to a day to dry and sometimes months to finish pouring it into place. If the concrete moves significantly, cracks and damages may appear on the road surface. This is especially important when laying roads in areas prone to earthquakes or floods.

When is Concrete Used for Roads?

While asphalt is the most popular choice for building roads, concrete roads are still required for specific areas and purposes. Concrete is a more robust and more durable surface than asphalt. As a result, concrete is an excellent lens material for heavy traffic roads and locations with severe weather.

When concrete is laid correctly by skilled professionals, it can last over twice as long as an asphalt road. For example, a concrete road in Germany that connects Hanover to Berlin was installed during world war two and is still in use today. Therefore, it makes sense to lay concrete roads when you desire a durable and long-term road installation.

In the US, about 60% of interstate highways are constructed using concrete, especially in urban areas. This is due to the heavy vehicles that pass over them constantly, which wears down asphalt quickly. Once installed, a concrete road can remain open and in good condition for decades.

If highways were constructed with asphalt, they would wear down quickly. This is not only disruptive to the flow of traffic, but the cost of regular repairs can quickly add up. Therefore in some cases, concrete is the more financially viable option over a long period.

Concrete roads that use rebar to add can easily last for over 50 years with the proper care. Asphalt roads, on the other hand, will need repaving every 10 to 20 years. This is a critical factor in the popularity of concrete roads in cities, highways, and urban areas.

When is Asphalt Used for Roads?

Unlike concrete, the primary use of asphalt is roads. Over 70% of all asphalt used in the US is used to construct roads and driveways. Asphalt has numerous advantages over competitors when it comes to costs and safety in the streets. However, in some circumstances, asphalt is required to pave the road.

In cold climates, concrete roads do not hold up very well. This is because the temperature changes can cause concrete to expand and contract. This allows water to pass into any cracks and gaps within the concrete. As the temperature drops below freezing, the water expands and becomes ice.

This expansion causes cracks and gaps to appear within the concrete road. Once cracks and holes appear on concrete, they can grow to become severe structural problems in a short time. As a result, repairs will be required to restore the road to working condition.

This issue is less prevalent with asphalt. Asphalt can grow and shrink with the temperature change. On top of this, asphalt is a porous material that allows water to pass through. This prevents the freeze-thaw action from wreaking havoc on the condition of the road.

However, asphalt is still vulnerable to damages caused by extreme weather but when damages occur, repairing asphalt is much cheaper and more accessible than concrete. If the road is in proper working condition, asphalt repairs are very reasonable; however, if the road is not in good condition, repair work will be more extensive and costly.

Are Asphalt Roads Expensive to Maintain?

The maintenance cost for asphalt roads varies significantly depending on where the road is located, how much traffic passes over the road, and the road’s weather conditions. Asphalt can be easily damaged and can wear down in just a few short years. This results in constant repairs and maintenance, which can quickly add up to high maintenance costs.

The average cost of maintaining asphalt roads in the US is roughly $8,500 per mile annually. One thousand miles of asphalt roads cost 8.5 million dollars to maintain. Some streets cost even more. Crack sealing, patching, traffic control, and repaving are all factored into this cost.

The cost of maintaining asphalt can significantly reduce in low-traffic areas as less strain is put on the surface by large vehicles. Also, pleasant weather conditions with less temperature variation can allow asphalt roads to last longer without needing maintenance.

Asphalt would be much more expensive to maintain if the material was not recyclable. Asphalt is one of the most commonly recycled materials on earth if measured by weight. Therefore to repair a surface, existing asphalt can be lifted, reheated, and laid down again. This cuts down on the cost of building materials and reduces the impact of asphalt on the ecosystem.

Asphalt roads are cheaper to install than concrete roads. However, the potential high maintenance costs can make concrete the more cost-effective option, in the long run, depending on several variables.

What’s the Cost of Maintaining Concrete Roads?

Unlike asphalt, the maintenance costs for concrete roads are relatively uniform in most cases. Concrete is such durable and dependable building material. As a result, concrete roads can last for decades with little to no maintenance or care.

However, concrete is often used for interstates and high traffic areas; this results in more expensive maintenance fees as more traffic results in more wear and tear for the concrete.

Concrete roads cost as little as $200 to $300 to maintain per mile in states such as Oregon. In other states, like New Jersey, one mile of concrete highway can cost up to half a million dollars to maintain. This is a high price considering the thousands of miles of concrete roads laid in the state.

If local weather conditions are suitable, concrete can be considerably cheaper to keep than asphalt throughout its lifetime. However, in some instances, the cost of maintaining concrete can be significantly higher. Therefore all factors need to be considered before deciding which building material is suitable for which roads.

Final Thoughts

Asphalt is commonly chosen over concrete as the building material used for roads for a couple of factors. Asphalt is cheaper to install and maintain. Asphalt is a safe driving surface that provides plenty of grip for vehicles to prevent accidents. On top of this, asphalt is quicker and easier to install, which reduces disruptions caused by road works.

Asphalt also provides a clear contrast in color between roads and road markings. This allows drivers to distinguish between signs and markings while traveling at speed quickly. As a result, drivers will experience a safer drive.


By Giovanni Valle

Giovanni Valle is a licensed architect and LEED-accredited professional and is certified by the National Council of Architectural Registration Boards (NCARB). He is the author and managing editor of various digital publications, including BuilderSpace, Your Own Architect, and Interiors Place.

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