Roads are made from a variety of materials around the world. Asphalt and concrete are the most common routes found in the US, and they require different supporting structures and installation processes.
Which roads, if any, have rebar built into them? This depends on whether they are built from asphalt or concrete. Asphalt roads do not require rebar as they have tensile and flexural strength.
Concrete roads have rebar built into them. Rebar provides the road with structural support that reinforces the road. This is an essential aspect of increasing the longevity and durability of concrete roads. Rebar is typically made out of steel or a wire mesh.
Keep reading to learn more about rebar, when it is or isn’t used in roads, and its advantages. We will also examine the drawbacks of concrete roads with rebar and where you can expect to find roads built with rebar.
What Is Rebar?
Rebar is a term used to describe metal rods that provide concrete structures with additional structural integrity. It is commonly made out of steel and is shaped to provide a frame for the concrete structure. Rebar may also be replaced with a wire mesh.
Rebar is used in most concrete structures or roads. It binds the concrete together, which allows the concrete to support more significant amounts of weight. Concrete structures equipped with rebar will also last longer as they are less susceptible to wear and tear.
When Is Rebar Used in Roads?
Rebar is used in the construction of concrete roads. Concrete structures are significantly stronger with rebar as the material lacks tensile strength, which can lead to deterioration. Rebar provides the concrete with structural support to counter this shortcoming.
A concrete road constructed without a rebar would be vulnerable to breaking and coming apart. Separation in a route can easily lead to a severe collision which too often leads to severe injury and death. To learn more about when rebar is used in road construction, check out this link.
Why Is Rebar Used in Roads?
The rebar is used on roads because it serves an essential function. It stops the concrete from separating and falling apart. This is due to the high compressive strength of concrete but the low tensile strength. Therefore, concrete becomes tough to crush but easy to pull apart when rebar is absent.
Perhaps the biggest issue with concrete is the cracks that appear over time. Using rebar during construction will not prevent cracks from occurring within the concrete. Instead, the rebar will hold the concrete structure in place after it has cracked, preventing the concrete from separating either side of the crack.
Therefore, concrete roads built with rebar will stay in shape long after initial installation. Concrete reinforced with rebar can last for decades with minimal care or maintenance. As a result, the cost of keeping roads in good condition can be significantly reduced. However, in certain weather conditions, concrete roads made with rebar can be costly to maintain.
When Are Concrete Roads Built with Rebar Unsuitable?
There are a few critical drawbacks to using concrete roads with rebar. Here are a couple of reasons why concrete roads with rebar may be unsuitable for use:
- Climate
- Construction Time
- Cost
Climate
Concrete is not an ideal building material for colder weather. When it is first poured and dry, it can be severely damaged if exposed to below-freezing conditions. This will result in quick deterioration.
Concrete can also be damaged by what is known as the freeze-thaw effect. When cracks inevitably appear in a concrete road, water can pass through and fill the gaps. Then when the temperature drops below freezing, the water expands as it turns to ice. This places the structure under pressure and causes the cracks and gaps to worsen.
Another major disadvantage to using concrete in colder climates is the fact that concrete does not absorb liquids. This results in snow and ice freezing on the surface of the road. As a result, drivers may lose traction when driving, which could easily cause accidents.
Therefore concrete is not an excellent material for road construction in frigid climates as it will require far more maintenance, and safety may be compromised. However, other materials are also vulnerable to harsh weather conditions.
Construction Time
Another reason concrete roads with rebar are not more common is installation time, which for a new concrete highway is significantly higher than for alternative materials like asphalt.
Therefore high traffic areas will be disrupted for longer if the concrete is used, leading to significant disruptions to businesses, especially in congested cities. The added time required for installing concrete roads also leads to another reason why concrete roads are often unsuitable.
Cost
Concrete is twice as expensive as asphalt to purchase the materials. Then on top of this, it requires more labor to install, which results in higher labor fees.
Concrete roads can also be costly to maintain in certain high-traffic areas. For instance, highways constructed using concrete and rebar in New Jersey are the most expensive roads in the United States to maintain. With annual maintenance fees regularly exceeding half a million dollars per mile.
Where Are Concrete Roads With Rebar Most Common?
Concrete roads with rebar are most common in interstate highways within the USA. This is partially due to the solid and durable nature of concrete that allows for heavy traffic to pass over without deterioration of the surface.
Concrete roads built with rebar are used in areas that have a lot of heavy traffic passing by. This is why they are found on highways and interstates and busy roads that regularly have large vehicles traveling over them.
Concrete with rebar is also standard in areas with sensitive natural ecosystems nearby. This is because concrete is a much more environmentally friendly material than alternatives like asphalt. Chemicals found in asphalt can make their way into streams and waterways. This can have a devastating effect on wildlife in the area.
Concrete also produces less carbon dioxide during production than alternatives. This is partly because it is made using widely available limestone. This reduces the emissions used during the transportation of the material. As a result, local governments concerned with climate change and reducing emissions opt for concrete with rebar roads.
Concrete with rebar is often found in urban areas and roads with poor lighting. This is because concrete effectively reflects light. Therefore fewer street lights are required at night when roads are made using concrete. Lighting costs can be reduced by as much as 30% with concrete roads.
The extra light provided by concrete roads can also improve visibility for drivers at night. Improved visibility can reduce accidents and prevent collisions during the night.
Conclusion
Asphalt roads do not require rebar. On the other hand, rebar is built into concrete roads to provide needed tensile strength. It supports concrete structures and increases the longevity of the surface.
Concrete has resistance to compression, but it has poor tensile strength. As a result, it is challenging to crush but easy to separate. Rebar prevents this and holds the concrete roads together.
Rebar is made from steel or a wire mesh. The concrete is poured with the rebar set in a specific location inside. This ensures that concrete roads remain solid and durable. The durability of concrete roads is one of the main reasons for interstate highways been using concrete with rebar.
