We walk on it, drive on it, play on it, and even park on it. Most runways on airports are made of asphalt too. But, have you ever taken some time to know what asphalt is? This is a composite material that's made of bitumen and mineral aggregates. Asphalt is very versatile, and has many applications. It is used in roads, airport runways, parking lots, driveways, and even in certain play areas. 

Ingredients

  • Two basic ingredients make asphalt—bitumen, and aggregates.
  • Aggregates – these make around 95% of asphalt. Aggregates comprise a mixture of gravel, sand, and crushed stone.
  • Bitumen – this makes the remaining 5%. It’s the dark or black viscous material, which binds together the aggregates. Bitumen is made of polycyclic hydrocarbons, which is a byproduct of petroleum.

To have a better understanding of the ingredients of asphalt, its elemental components include hydrogen, carbon, oxygen, sulfur, and nitrogen. Also, there are some traces of nickel, vanadium, and iron in asphalt. 

Types of asphalt

According to Florida asphalt paving contractor ABC Paving, a paving contractor can use different types of asphalt mixes to achieve optimum performance in different applications. Different requirements, like the weight of vehicles, traffic flow, temperature, noise reduction requirements, as well as weather conditions determine the type of asphalt used on a certain surface.

The type of asphalt used must have sufficient resistance and stiffness to deformation for it to handle the pressure applied by vehicles. However, it should also have enough flexural strength, which should allow it to resist cracking, which can be caused by different pressures exerted on the surface.

However, the contractor must ensure that they observe good practices when installing asphalt. This ensures that it’s fully compacted for optimum compatibility.

Production of asphalt

Asphalt is made in a typical asphalt plant, which can either be a mobile mixing plant or a fixed plant. A typical asphalt plant can produce an average of 800 tons of asphalt per hour. The temperatures used in the production of asphalt do differ, depending on the production technique. This shall be discussed below. 

Cold mix asphalt (CMA)

The aggregate is not heated when producing cold mix asphalt. Bitumen mixed with water is used when making cold mix asphalt, and it breaks when mixing or compacting the asphalt—thus producing the coating for the aggregate.

As the asphalt cures, the water starts to evaporate, thus strengthening it. Cold mix asphalt is highly recommended for areas with light traffic. 

Warm mix asphalt (WMA)

Typically, warm mix asphalt is produced at an average temperature of 120 – 140 degrees C. Less energy is used when producing warm mix asphalt. Also, fewer fumes are produced, in this process. During the paving process, the temperature of the asphalt is significantly lower, and this makes the working conditions favorable for the pavers. Also, this makes it possible to open the road within a short period of time. 

Hot mix asphalt (HMA)

Hot mix asphalt is produced at a temperature of around 150 – 180 degrees C. However, a different asphalt mixture can be used in the production process, and this depends on the usage of the product. 

Durability

There’s a possibility that you’ve ever seen a crack or pothole in an asphalt paved road. This is an indication that asphalt doesn’t last forever. The durability of asphalt depends on several factors. Some of these factors include temperature changes, moisture, exposure to some chemicals, or the volume of traffic. Also, different asphalt ingredients do determine the durability of the product.

Since asphalt can support the weight of heavy loads, it’s the most preferred material for paving roads, driveways, and parking lots. This product can be applied quickly, and repaired easily by pressing it onto potholes and cracks.

With time, the ingredients can start to decay and erode as a result of exposure to weather elements, heavy traffic, as well as expansion and contraction. Thus, seal coating asphalt paved surface is essential to keep the paved surface in good condition. Although today we have numerous sealing products, experts recommend that you use coal & tar asphalt sealer. This sealer provides optimum protection against water, oil, traffic, salt, as well as other staining materials.

Failing to protect an asphalt paved surface through sealcoating, it will eventually crack. Also, leaving small fissures and cracks unrepaired and exposed, they become bigger, leading to significant damage like crumbling of the asphalt, potholes, as damage to the foundation. At the end of the day, you will end up replacing the asphalt. 

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