One of the most widely used road paving materials for driveways and parking lots is asphalt. It is durable and smooth which makes it a favorite to be used in infrastructure projects in the United States. But though asphalt is typically characterized by its durability, it is susceptible to cracks in the long term. The hardness of the asphalt is one of the major reasons it leads to such cracking. This article will discuss how harder asphalt may cause cracking and how to avoid it so that your paved area can be smooth and functional as long as possible.
Understanding Asphalt: What Is It Made Of?
In order to understand how harder asphalt may cause cracking, it is important to understand what asphalt consists of. Asphalt is a combination of bitumen (a viscous, black material) and aggregates (sand, gravel, crushed stone, and so on). This blending produces an elastic and strong material that is suitable in road construction and other paving projects. The precise combination of the asphalt mixture is related to its purpose; each type of mixture has various ratios of bitumen and aggregates.
Asphalt Grades and Types:
Hot Mix Asphalt (HMA): This is the most popular asphalt and it is utilized in highways, driveways, and parking lots.
Warm Mix Asphalt (WMA): Produced using lower temperatures in order to cut emissions.
Cold Mix Asphalt: Used to patch roadways under colder weather.
The flexibility of asphalt is due to its capability of adapting to the temperature and traffic loads. As asphalt becomes old and hard, however, it becomes less flexible in adapting to such conditions, and the asphalt cracks.
What Happens When Asphalt Hardens?
Oxidation and age are some of the reasons that make asphalt harden. As much as hardened asphalt is initially flexible and capable of absorbing stresses, it becomes non-elastic. That is, its chances of cracking are increased when it is exposed to external pressure as a result of traffic, weather conditions, and temperature changes.
Factors Contributing to Hardening:
UV rays: UV rays of the sun cause the bitumen in asphalt to be broken down and harden, making it brittle.
Oxidation: The bitumen contained in the asphalt reacts with oxygen when exposed to the air, resulting in hardening. This process is gradual but inevitable over time.
Weather changes: Hot temperatures lead to softening of the asphalt and cold temperatures may make it brittle. When the temperature changes frequently, it may result in stress on the material making it crack.
How Harder Asphalt Leads to Cracking
Asphalt becomes more rigid than it is supposed to be, and therefore, becomes less flexible and easily prone to cracking.
Now, we can discuss the relation between hardness and cracking in greater detail:
Increased Brittleness
When asphalt becomes hard, the bitumen is harder and less flexible. This causes the asphalt to become brittle and it is unable to bend or to shift with changes in temperature, traffic load, or environment. This increases the probability of the material cracking when subjected to pressure.
Reduced Ability to Absorb Stress
Flexible asphalt can take the strain of traffic, weather, and environmental conditions. But when asphalt becomes excessively hard, it is unable to support the strains put on it anymore. This is particularly bad in places with congestion or severe weather. The asphalt may split under such pressure leading to cracks on the surfaces or even more structural damage.
Shrinkage
When asphalt hardens, it can also shrink. This shrinkage results in internal stress, and then, cracks develop at the surface. Such cracks can be seen in the form of longitudinal cracks (cracks along the direction of traffic) or transverse cracks (cracks across the direction of traffic).
The Impact of Cracking on Asphalt Surfaces
Cracking is not only an aesthetic problem, but can also result in more serious problems unless treated early enough.
So how can cracked asphalt impact your paved surfaces?
Water Penetration
Water may easily intrude into the asphalt surface once there are cracks. After a period of time, water gets into the cracks and the material expands and contracts. This exacerbates the cracking, leading to further damage. One of the major causes of potholes is water penetration because the water wears away the subbase that lies beneath the asphalt.
Structural Damage
Cracks can compromise the structural integrity of the asphalt. Untreated, the cracks may extend and cause bigger gaps or even pavement collapse. This is more so in regions where the traffic is heavy since heavy vehicles can further destroy the damaged area.
Aesthetic Concerns
The appearance of your driveway, parking lot, or road can be ugly due to cracked asphalt. This has the ability to reduce the curb appeal of a home, which influences the value and leaves an undesirable impression to visitors or prospective buyers.
How to Prevent Hard Asphalt from Cracking
Proper Mix Design
The correct asphalt mix is one of the most effective methods of avoiding premature hardening. Different mixes are designed for different climates and conditions. An example is that a mix that contains a higher percentage of bitumen may enable the asphalt to last longer as a flexible material. When you work with a professional paving company, they will make sure that the proper mix is chosen according to your needs.
Sealcoating
Sealcoating refers to a preventive activity where a protective layer is applied over the asphalt. This layer assists in protecting the asphalt against UV rays, oxidation, and water damages that all lead to hardening and cracking. Your asphalt should be sealcoated every two to three years to maintain its good shape.
Regular Maintenance
Small cracks may be prevented from growing bigger with regular maintenance such as filling cracks and patching. When you seal any cracks that appear immediately, you will avoid moisture getting into the surface, thus maintaining the integrity of the asphalt.
Proper Drainage
Proper drainage of your asphalt surface can ensure that the water does not gather on the surface or find its way into cracks. Drainage systems or surface grading that will cause the water to run off will aid in preventing the water-related damage that further increases the cracking.