Jobs in Construction: The Science Behind Asphalt: Composition, Properties, and Performance

Iowa State University’s Institute for Transportation says,”The United States has a lot of roads—3,980,817 miles to be exact. Roads are relatively simple but make a big impact, and they exist nearly everywhere, guiding traffic and travelers from one side of the country to the other. But it didn’t happen all at once. And the “first roads” definitely didn’t look like the roads we use today. Usually paved with asphalt or concrete, our roads today are relatively smooth, sturdy, and durable. Some roads even support millions of vehicles per day. But the first roads—not just in America but in the world—were a little more simple, although important all the same.”

Asphalt is an ever-present material in the construction industry, used in roads, driveways, parking lots, and more. Because of its sturdiness, it can be found throughout the entire world. Its many uses and durability make it a first choice for infrastructure projects and jobs in construction.

Composition of Asphalt

We start with the composition of asphalt, which is a mixture of aggregates, binder, and filler. Aggregates, such as sand, gravel, and crushed stone, provide the bulk and strength to the asphalt. The binder, typically bitumen or asphalt cement, acts as the glue that binds the aggregates together. Fillers, like hydrated lime or Portland cement, are used to modify properties such as stiffness and durability.  The exact composition of asphalt can vary based on factors like climate, traffic volume, and the desired performance characteristics. For example, in regions with extreme temperature fluctuations, additives may be included in the mix to help with thermal stability and to prevent it from cracking.

Properties of Asphalt

Understanding the properties of asphalt is crucial for designing durable and long-lasting pavements. Asphalt exhibits viscoelastic behavior, meaning it can deform under stress and return to its original shape once the stress is removed. This property allows asphalt pavements to withstand heavy traffic loads and thermal expansion/contraction without much damage.

The stiffness of asphalt, often measured using parameters like stiffness modulus and fatigue resistance, determines its ability to distribute the different loads and resist deformation. Higher stiffness is wanted for heavy-duty applications, such as highways and airports, while lower stiffness may be suitable for residential streets or parking lots.

Another important property is rutting resistance, which refers to the ability of asphalt to maintain its shape by having repeated traffic loads use it. By adjusting the asphalt mix design and incorporating additives, engineers can improve rutting resistance and prolong the life of the pavement.

Performance of Asphalt

The performance of asphalt pavements is influenced by many different factors, including design, construction practices, maintenance, and environmental conditions. Proper pavement design considers traffic volume, axle loads, climate, and subgrade conditions to ensure the right thickness and structural support. During construction, factors such as compaction density, temperature control, and the quality of materials play a critical role in achieving a durable pavement. Adequate compaction removes air voids and enhances the bond between aggregates and binder, leading to improved strength and resistance to moisture damage.

Regular maintenance is needed in order to keep the roads in good condition. This maintenance includes crack sealing, surface treatments, and rehabilitation, and is essential for extending the service life of asphalt pavements. Timely repairs and preventive measures can help lessen issues such as potholes, rutting, and surface deterioration, preserving the infrastructure investment and creating many jobs in construction.

Environmental Considerations

Asphalt Pavement Alliance says, that it is 100% reusable and recycled at a higher rate than any other material used in the United States- this includes soda cans and newspaper. Asphalt production and construction activities can have environmental implications, including energy consumption, emissions, and waste generation. Sustainable practices, such as using recycled asphalt pavement (RAP), warm mix asphalt (WMA), and reclaimed asphalt shingles (RAS), are gaining popularity to reduce the environmental impact.

RAP allows for the reuse of existing asphalt materials, conserving natural resources and reducing landfill waste. WMA technologies lower production temperatures, leading to energy savings and reduced emissions of greenhouse gases. Incorporating RAS into asphalt mixtures provides additional benefits, such as improved binder properties and reduced costs.

At Kilgore Companies, we prioritize environmental stewardship and innovation in our asphalt technology. By embracing sustainable practices and constantly exploring new materials, we aim to minimize our footprint while delivering high-quality infrastructure solutions to our customers.

Jobs in Construction

In the construction industry, jobs related to asphalt include asphalt technicians, paving operators, quality control inspectors, and pavement engineers. Asphalt technicians play a crucial role in testing materials, monitoring production processes, and ensuring compliance with rules and regulations. Paving operators operate heavy equipment, such as asphalt pavers and rollers, to lay and compact asphalt mixtures according to design plans. Quality control inspectors conduct tests and inspections to verify the quality and performance of asphalt pavements, identifying any issues that require corrective action. Pavement engineers are responsible for designing, analyzing, and optimizing asphalt pavements for different applications and conditions. They use advanced software tools, perform structural evaluations, and recommend maintenance strategies to maximize the life and performance of the asphalt. 

As the construction industry continues to get better, jobs in construction and asphalt-related professions are abundant.

Sustainable Construction

As discussed previously, asphalt paving involves different processes. Such as mixing, laying, and compacting the asphalt mix to different thicknesses, smoothness, and density depending on the the need. The quality of the asphalt has to be checked by inspections, testing, and it has to adhere to certain standards. By regular maintenance procedures, including crack sealing and treatments, the integrity of the asphalt can last longer.  Asphalt is a versatile and durable material essential for modern infrastructure. Understanding its composition, properties, and performance is a huge part needed in designing and constructing high-quality pavements that withstand the environment and time. By embracing sustainable practices and investing in talent, the construction industry can continue to innovate and meet the evolving needs of society. At Kilgore Companies, we are committed to excellence in asphalt technology and creating a sustainable future for many generations to come. Head to our website to learn more about sustainable construction and to find jobs.