The decision making process for selecting paving materials is often based on the initial cost of asphalt vs concrete roads. However, several factors need to go into your evaluation of asphalt vs concrete roads for a new highway or replacement of an existing road.
While the price is always a factor, you also need to think about the paving material’s other five inherent factors. Evaluate how it is made, lifetime durability, maintenance requirements, expected traffic impact, climate effects, and the environmental impact of the type of product you choose.
Asphalt vs Concrete Roads – How They Are Made
Asphalt is a manufactured aggregate comprised of a smooth blend of bituminous oil, sand, and gravel. When roads are built using asphalt construction, hot asphalt is poured onto a heavier aggregate bed of gravel and pressed into it with a steamroller.
Once the asphalt cools, it is strong enough to withstand automobile traffic. Asphalt is smooth, black, and does not absorb water. While asphalt is tough and durable, it offers enough flexibility to adjust to imperfect underlying surfaces.
When choosing asphalt or concrete for your project, consider the following:
- The initial cost of building asphalt vs concrete road
- Long term durability and maintenance costs
- How climate affects which road type you need
- Impact of traffic type and quantity
- Environmental impact
The National Asphalt Pavement Association cites three key reasons to choose Asphalt for your road-paving project:
- Asphalt is the most popular road surfacing material in the USA, as 94% of roads in the U.S. are asphalt.
- Asphalt paving construction can be completed quickly. Traffic delays for both commuters and long-haul truckers will be minimized. You’ll be able to drive across your new asphalt surface in three to four days. Concrete, on the other hand, must cure for seven days after it’s poured before it can bear the weight of vehicles.
- Asphalt holds up better under harsh weather conditions and provides a smoother ride. Concrete can be eroded by salt during winter and has a brushed or tined surface, which is not smooth and can create a noisier ride.
Concrete consists of binding material called cement, composed of lime, silica, alumina, and gypsum, which are mixed with sand, aggregate and water.
As the mixture dries (cures), it forms a stiff, unforgiving solid surface. The natural color of concrete is grey, but adding colors provides almost any desired shade.
The Portland Cement Association boasts three facts that should cause you to choose Concrete for your road-paving project:
- Concrete holds up better than asphalt under heavy traffic and heavy truck volumes and is easier to see at night due to it’s lighter color.
- Concrete pavement requires little to no maintenance throughout its life.
- Unlike asphalt, it does not need repeated resurfacing, patching, or spot repairs.
1. The initial cost of building asphalt vs concrete road
Concrete can cost, on average, 50 percent more than asphalt, making asphalt a better value for your money. Asphalt can run about $4 to $6 per square foot.
Concrete is usually the most expensive option initially. Concrete can cost 2-3 times as much as asphalt and about 6X the gravel cost. Concrete can run $5 to $10 per square foot.
2. Long term Durability and Maintenance costs
Along with the initial cost of the paving material, you should also evaluate the life-cycle costs, of which the cost to maintain the road and durability are a large part.
Asphalt is a durable material that is weather-resistant. When you drive on roads built with asphalt, its smooth surface will provide optimum tire contact with the driveway, increasing skid resistance.
Asphalt has higher annual maintenance costs than concrete. You may need to apply top layer sealants, depending on your climate. Those sealants may need refreshing every 3 or 5 years.
However, repairing an asphalt roadway is simpler than a concrete road, as total removal and reconstruction are not needed. Just the top layer of asphalt is removed and replaced. The asphalt material removed can then be recycled.
The typical asphalt road will last 20 – 30 years.
Concrete, if installed correctly, has two to four times the lifespan of asphalt and is easier to maintain.
Concrete is considerably less prone to wear and tear defects like rutting, cracking, stripping loss of texture, and potholes that can occur with flexible pavement surfaces like asphalt. However, Concrete is prone to cracking under extreme pressure and is costly to repair. Holes or cracks can’t be patched–instead, entire slabs must be replaced.
- A recent PCA survey concluded that concrete pavement lasts 29.4 years on average before a significant rehabilitation is required.
- Asphalt pavements required a significant rehabilitation after 13.8 years.
Over time, the average asphalt pavement can cost up to three times more.
Concrete has the longest lifetime and will need to be replaced only about every 30 to 40 years.
3. How climate affects which road type you need
Temperature changes, the impact of the sun’s heat, snow and ice, and rain, all can take a heavy toll on roadways.
Asphalt’s black color absorbs the sun and facilitates snow and ice melt. If the sun can’t reach the surface, it’s okay to apply salt because chemicals won’t damage asphalt.
Asphalt road provides better safety of the vehicle against snow and skidding. The reason is that its surface isn’t as rigid, allowing it to expand and contract depending on the climate.
Asphalt can soften and crack over time as it is exposed to moisture and sunlight. As water percolates into the asphalt, it widens the cracks leading to distorted and unattractive surfaces.
- Cold weather can cause concrete to expand and contract, leading to cracking.
- Concrete can also be damaged by road salt. Salt damages concrete over time by causing corrosion to occur under the surface, causing cracking and crumbling.
- Finally, concrete is slippery when icy or rainy providing poor vehicle traction.
4. Impact of traffic type and quantity
Pavement wearing is a process involving deterioration by vehicle and load other. Factors influencing this type of wear are the actual traffic load or volume and the vehicle type.
Passenger cars have little effect on a pavement’s service life from a materials fatigue perspective.
A number of experiments were conducted by the American Association of State Highway and Transportation Official (AASHO) to determine how traffic contributed to the deterioration of highway pavements. According to the results of AASHO Road Test, heavily loaded trucks can do more than 10,000 times the damage done by an average passenger car.
An asphalt surface will generally be constructed for high-volume primary highways that have an average annual daily traffic load of greater than 1200 vehicles.
All asphalt pavements have a bridging action that makes them flexible, which means they can withstand occasional overloads without serious damage to the road. Asphalt pavements can be designed to suit any type of conditions for traffic, soils, and materials.
Asphalt is a popular pavement material for low- and medium-traffic roadways, and has proven itself over time under heavy truck traffic in urban and rural settings.
Heavy vehicles like delivery trucks put a lot of pressure on asphalt roads. Consistent stress on asphalt can cause different types of cracks and lead to the formation of potholes.
High traffic counts and heavy truck volumes make concrete a desirable choice because it simply holds up better under heavy loads. State departments of transportation tend to go with concrete on interstates.
Concrete is regarded as less susceptible to rutting, frost heaves in colder climates and stresses related to the constant pounding it takes from heavy loads.
5. Environmental impact
For pavements, each phase of the life-cycle, including raw materials production, construction, maintenance, use, and end-of-life, poses a unique burden on the environment.
The LEED Green Building Rating System used by many contractors is a scorecard for the design, construction, and operation of green buildings. Pavement type selection of asphalt vs concrete road can contribute directly to some LEED credits.
Asphalt pavements require 20 percent less energy to produce and construct than other pavements. Asphalt paving is a sustainable construction process. When appropriately designed and built, the road itself doesn’t wear out.
Asphalt pavements do not leach. Once they are constructed, asphalt pavements have a low environmental impact. Studies show asphalt pavements and stockpiles of reclaimed asphalt pavement don’t leach.
Asphalt is recyclable. The asphalt industry reclaims about 65 million tons of product every year and reuses or recycles about 99 percent of it.
According to a Department of Transportation Study, concrete has a low lifetime impact on the environment due to its lower energy cost initially, better recyclability, and lower lifetime reflection of sunlight into the atmosphere.
The Construction Materials Recycling Association estimates that about 140 million tons of concrete are recycled each year in the U.S., reducing the construction projects’ environmental impact.
Concrete does not rust, rot or burn, saving energy and resources needed to replace or repair damaged buildings and infrastructure.
- While each paving material has some environmental benefits, neither is a sustainable product. Asphalt and concrete are made from materials that are drilled for or mined and have an adverse environmental impact.
- Both surfaces are impermeable, leading to water runoff and potential problems for local water treatment facilities, rivers, and streams.
- Both release Volatile Organic Compounds (VOC). Petroleum-based asphalt is a high volatile organic compound. As the product converts to asphalt, significant quantities of harmful greenhouse gases are released into the atmosphere. The cement producing process for concrete requires high levels of heat and generates significant VOC emissions.
Asphalt vs Concrete Roads: a side-by-side Comparison
|Composition||Aggregate made from bituminous oil, sand, and gravel||Aggregate made from sand and crushed rock, cement, and water.|
|Initial Cost||Average cost $4 to $6 per square foot||Average cost $5 to $10 per square foot|
|Durability||Asphalt has an average service life of 20-30 years.||Concrete has an average service life of 30 to 40 years.|
|Maintenance Requirements & Costs||Asphalt roads require resurfacing every 3-5 years.||Concrete roads require Low maintenance requirements and costs.|
|Climate impact||Asphalt offers better safety against snow, ice & skidding. Extreme heat can cause asphalt to soften.||Concrete does not soften in warm climates. Extreme cold can cause cracking.|
|Environment impact||Asphalt requires 20% less energy to produce but can emit greenhouse gases.|
Asphalt doesn’t leach and is recyclable.
|The use of industrial byproducts in concrete lowers energy usage and reduces the generation of greenhouse gases. |
Concrete can be 100% recycled at the end of its service life.
Choose a full-size contractor able to do large-scale roadway construction that is reputable, has been established for some time, and offers a guarantee on their work.
- The cheapest contractor is usually not the best contractor for the job. However, the highest-priced contractor does not always mean they are the best. Be sure you get estimates from several contractors. Look at the cost of the proposed materials, and ask for testimonials.
- Contractors vary in their experience, sourcing of materials, and pricing. Beware of estimates that are significantly lower or higher than all of the rest, as that can be a sign of inexperience, low-quality materials used, poor workmanship, or price gauging.
- Don’t even think about working with a contractor that does not guarantee their work.
As with all large projects, do your homework.
Thoroughly evaluate the five factors we’ve discussed and the ultimate use for your project to consider whether to choose asphalt vs concrete roads. When considering cost, be sure to look at both the initial cost and the life-cycle cost. The paving material that offers the most advantages for your project needs is going to be your best choice.
Look for paving contractors that have been in business for a while. They should have good testimonials and reviews for projects that are similar to yours. Ask other business owners for their paving contractor referrals. Be sure to consider all the factors discussed in this article for your road-building project, and choose your contractor carefully.