Pavement construction may seem easy, but there are many factors in deciding the optimal design for the surface. Asphalt pavement is the most desirable material to use when constructing airport and military runways, as the pavement structure must withstand tremendous amounts of weight. You need a medium that can hold up heavy usage, and asphalt pavements fit those criteria. Well-designed pavements can even cut vehicle operating costs.
In the United States, the Federal Aviation Administration (FAA) has strict requirements for runways that are intended to ensure the safety of everybody aboard the aircraft. Utilizing asphalt in constructing the runways is one of the best ways to make sure you are staying within FAA guidelines and operate on well-performing asphalt pavements.
This guide will walk you through everything you need to know about the material, including how it’s used to create the strongest possible ground route for planes.
What Is Asphalt Pavement?
Asphalt roads and pavements can be found everywhere. The material is highly durable and resilient, and often the preferred option for paving surfaces. There are many types of asphalt mixtures for pavements, with the most popular being hot mix asphalt (HMA): stone, sand, additives, and liquid asphalt bound together by asphalt cement (a product from crude oil and known as “asphalt binder”).
Asphalt pavements are made up of 90% to 95% stone and sand, with the remaining 5% to 10% being liquid asphalt. The United States has 3,600 asphalt production sites, according to the National Asphalt Pavement Association, and 94% of the roads are made of asphalt.
It takes a multi-step process to create the HMA pavement:
Step 1. Pre-Dose
This step involves weighing the aggregate components using a belt weighing instrument, allowing the substances to simultaneously be weighed and advanced to the next step of the process.
Step 2. Drying the HMA
During this step, a rotary drying drum dries all the components at a temperature of 300 degrees Fahrenheit. Drying can alter the components’ weight, so they are weighed a second time once the process is complete before being sifted and stored in silos.
Step 3. Mixing
The aggregate components are then transferred to the mixer. The asphalt binders are kept in a separate heated tank to maintain their liquid state to become suitable for mixing. The asphalt is then added to a mixer with the other components, and everything is thoroughly mixed together to create the asphalt paving material.
Step 4. Storage
The hot mix asphalt is stored in heated silos, then transferred onto dump trucks that transport the hot asphalt to job sites.
The asphalt paver will then use paving equipment to lay down new asphalt pavements on the road or runway. There are several advantages to using this asphalt mix for your runway project, including:
- It is cost-effective. Between the initial low-cost of the substance and its longevity, there is a relatively minimal cost involved in using asphalt to create a runway.
- It is durable and can handle immense amounts of weight as well as various environmental and weather conditions.
- Once installed, the asphalt pavement can be used almost immediately without an extended wait.
It is also often smoother than other types of surfaces. The method of installing the asphalt in multiple layers helps create a continuous flow of the medium.
Why Asphalt Pavement Is Perfect For Airport & Military Runways
Airport and military runways have strict guidelines for constructing pavements. The pavement surface should be able to withstand cold temperatures, have good rut resistance and fatigue resistance, and hold heavy weights, for example. A perpetual pavement that can last up to 50 years is efficient for runways as well. The versatility of asphalt pavements make it perfect for the unique challenges faced when creating runways.
Here are several critical benefits that make asphalt pavement the best material to use in runways.
1. Good Skid Resistance
Good pavement performance means there is a good skid-resistant pavement design. Asphalt is the perfect substance for such design, especially for runways where the planes take off and land constantly. Those operations require higher speeds, making aircraft more vulnerable to skidding and aquaplaning on runways in adverse weather conditions.
2. Surface Water Drainage
Surface water drainage is an essential factor in the pavement design process of airfield runways. A powerful drain can minimize the chances of a plane aquaplaning. Aquaplaning is when a vehicle slides uncontrollably on a wet surface. Airplanes have to operate in rainy and wet conditions, so good drainage is vital for the runways. Using porous asphalt can act as a drainage layer to prevent surface water from affecting the airplane tires’ grip on the pavement.
3. Sufficient Strength
Airplanes are heavy machinery, and they weigh even more when you consider the weight of the people and luggage in the aircraft. When the pilot is operating the plane along the runway during a takeoff or landing, the vehicle’s full weight is on the runway. A few things to keep in mind:
- The specific aggregate used in the asphalt mixture determines how strong it is.
- The binder layer is a load-bearing mixture of the elements.
- The binder must be strong enough to hold the stress intensity factors; otherwise, fatigue cracks will occur faster.
- Fatigue cracking is when the top layer begins breaking apart due to the perpetual weight of the vehicles operating above.
- You may have seen fatigue cracks in parking lots, concrete sidewalks, or other thin asphalt roads.
The runways are also made with thicker pavements to slow the aging process and fatigue cracking. If you need to construct a runway for airport or military needs, asphalt pavement is the right substance.
Speak With an Expert
If you are tasked with building a runway, don’t do it alone. Contact Limitless Paving & Concrete today to speak with an expert about the asphalt pavement questions you might have. Our team has years of experience in the field, and we can walk you through the process to ensure that you are choosing the proper asphalt for your needs.