Enhanced Durability to Improve Pavement Performance

One of the most common questions in the pavement industry is, “How long will it last?” Pavement is quite durable, of course, so it’s easy to tell clients their new road or parking lot will likely last twenty years with proper maintenance. However, the real answer isn’t quite so simple. Weather, UV index, and chemicals all affect the durability of pavement, as well as the type of load the pavement bears. Pavement durability, then, is an important topic, and there are a few ways to enhance durability.

Three Methods to Enhance the Durability of Pavement

Increase Density 

Increasing the density of pavement is the first and best way to improve durability. The way to increase density is by compacting the pavement to decrease the air pockets between the aggregate. In previous studies, a one percent increase in density results in a ten to thirty percent reduction in air voids. This is a significant difference, as air voids can quickly lead to pavement fatigue and alligator cracking, the first signs of poor pavement durability. Compacting the mix at optimal temperatures and at the correct times for each stage of compaction is mandatory. If the mix cools too much during a compacting stage, or the rollers aren’t matched well to the mix, the pavement won’t compact properly. Choosing the right mix for compaction is important as well, as the binder in the mix is what draws the aggregate together tightly. The better the binder, the less voids there are in the pavement. By choosing a high quality mix appropriate to the job and using the right compaction methods at appropriate times, the pavement will be denser and last longer.

Reduce Permeability

Permeability in pavement allows water and chemicals to seep inside, which can weaken or damage the pavement, particularly in a freeze-thaw cycle. Unless the pavement is designed to be permeable (porous concrete or permeable asphalt), a good way to increase durability is to reduce the permeability. This is best accomplished by using a mix appropriate to the required strength for the project. Larger aggregates within the mix will increase permeability, while mixes with finer aggregates will decrease it. Using aggregate blends instead of a single type of aggregate can also decrease permeability. With finer mixes and smaller aggregate, more asphalt binder is needed, which also increases the durability of the pavement. Another issue related to permeability is adequate water drainage. If the pavement has excellent drainage, permeability is less of an issue.

Protect from Chemical Damage

Chemicals, particularly deicing chemicals, can wreak havoc on pavement once they penetrate the surface. One of the best ways to keep pavement durable is to sealcoat pavement regularly. Sealcoating replenishes the oil and binders within the pavement, but it also seals small cracks and fractures to prevent chemicals from penetrating. It blocks UV rays that dry out the pavement and cause more damage. Once the pavement has been installed, sealcoating becomes the best way to increase durability throughout the pavement’s lifetime.

Pavement durability and the best ways to achieve it are so important that the Asphalt Institute runs workshops and webinars on this topic. Two webinars are available on compaction and durability:

  • Asphalt Pavement Compaction: Best Practices for Durability and Smoothness, available for a fee of $50.00
  • Intelligent Compaction: A Quality Control Tool for the Construction of Asphalt Pavement, available for free.

The Asphalt Institute also offers more recorded webinars that may be of interest. Find all webinars and workshops on offer at Training – Asphalt Institute.

The Federal Highway Association also reports on various topics, including the durability of pavement. If you’re ready for some in-depth reading on the topic, put on your reading glasses and check out the following reports:

Durability in pavement is always going to be a balance between the pavement’s function and its design. A little extra effort and knowledge can go a long way to enhancing pavement durability and extending its use for years, which means the answer to “How long will it last?” can truly be twenty years.