75+ Years Experience In Asphalt

Asphalt is a refinery-produced, petroleum-based material that plays a crucial role in modern infrastructure. Recognizable by its distinctive black color, asphalt is aesthetically appealing and incredibly durable, making it an ideal choice for Colorado roads, parking lots, and various construction projects.

One of the standout features of asphalt is its ability to be made from recycled materials, which aligns with Colorado’s sustainable practices toward an eco-conscious world.

Bitumen, a thick and sticky substance derived from crude oil, is the primary material used for asphalt concrete production (HMA). The composition of asphalt concrete is approximately 95% sand, gravel, and crushed stone, and 5% bitumen (liquid asphalt).

This component is NOT impervious but has exceptional waterproofing properties while supporting traffic loads. When designed and installed properly, it also protects the underlying structural section and subgrade.

Understanding the fundamental differences between asphalt and concrete is crucial when choosing between them for your Denver (front range) paving needs. Several primary components are considered when choosing between the two; however, we illustrate five: composition, aesthetics, uses, cost, and longevity. 

The composition of these materials plays a significant role in their performance. Asphalt is made of bitumen combined with aggregates, making it flexible and ideal for areas that experience heavy traffic or temperature fluctuations, which is expected since Colorado experiences all four seasons. On the other hand, concrete is made of cementitious materials mixed with water and aggregates, resulting in a material known for its strength and rigidity. Asphalt is a flexible pavement, while concrete is a rigid pavement. Asphalt also promotes snow and ice melt more effectively than concrete because the black surface attracts and retains heat, whereas the light gray color does not. 

Aesthetically speaking, the primary difference between asphalt and concrete is color. Their appearance sets them apart. Asphalt is dark black, sleek, and modern-looking, but it oxidizes over time, fading the color. Concrete is light gray and typically maintains its appearance for the life of its intended use.

Asphalt is used primarily for parking lots, roadways, highways, streets, and some pedestrian pathways. Concrete is used for curbs, gutters, sidewalks, trails, pedestrian walks, parking lots, streets, roads, and highways. Concrete is also used for structures, retaining walls, parks, and bridges. 

The initial cost per square foot of an asphalt section is typically cheaper than concrete. However, flowlines, traffic indexes, turning movements, and point loads can make concrete the better, and sometimes only, cost option. Again, both products are complementary and depend on the subgrade conditions upon which they are built. In conclusion, concrete sheds water on flatter slopes, whereas asphalt does not. Thus, the use choice will depend on engineering, design conditions, project budgets, and aesthetics. 

Depending on design, engineering, and initial investment choices, asphalt can last up to 40+ years. However, this lifespan is not set in stone; several factors can significantly influence how long your asphalt will remain in good condition, especially in Colorado.

One of the most critical elements is traffic. High traffic volumes with heavy point loads can deteriorate the asphalt section more quickly, leading to cracks and deterioration that may necessitate earlier repairs or replacement. Similarly, weather conditions are pivotal—extreme heat, heavy rain, and the freeze/thaw cycle can all damage asphalt integrity. Poor subgrade conditions and slopes flatter than 1.5% can promote premature pavement failure and shorten the design life. 

Moreover, regular maintenance and surface treatments are crucial for extending the life of your asphalt. Even a high-quality installation supported by an adequate composite section and subgrade can succumb to environmental stresses without proper care. Additionally, the geotechnical quality of the soil beneath the design section affects its longevity; unyielding, unstable, or improperly compacted materials can lead to cracking and pavement failures.

Understanding what causes asphalt cracks in Denver’s semi-arid, high-desert climate, which is subject to extreme temperature variations, is essential for maintaining the longevity and integrity of your pavement. Several key factors contribute to this deterioration, and knowing in advance can help prevent future repairs. 

First and foremost, understanding the existing subgrade conditions is key to minimizing/prolonging cracking. Perched moisture immediately under the HMA section will promote cracking and failure. Some subgrades are free-draining, while the majority of Frontrange materials are not. Investing in a non-plastic-free draining aggregate base section that lies immediately below your HMA section will enhance longevity, reduce cracking frequency, and reduce maintenance costs.

Moreover, poor installation practices cannot be overlooked. If the subgrade and pavement section(s) are not installed correctly and/or subpar materials are used, cracking and pavement failure will occur. Harsh weather conditions compound this issue; extreme heat during dry Colorado summers and cold, wet winters can compromise pavement sections via the freeze/thaw cycles and expansion/contraction cycles. This leads to pavement cracking. Again, investing in your subgrade and installing a composite section when needed using the proper base section prolongs surface cracking. Surface cracking can also be controlled by installing control joints with backer rods and a rubberized crack-fill product. We normally see control cracking products on airports and large surface areas of HMA.

Lastly, an overabundance of traffic (high traffic indexes), with heavy truck traffic, puts immense stress on your pavement within the wheel paths. Vehicle weight and constant movement can exacerbate existing weaknesses in asphalt structure. Other causes that promote failure include tree roots, harsh weather conditions, and increased traffic movement onto a lighter traffic design. By recognizing these factors, you can preserve the integrity of your asphalt for an extended period, depending on the application. 

Understanding the correct time and surface treatment is crucial for proper asphalt maintenance, especially in Denver's varied climates. Depending on your maintenance program, the timing of application, and infrastructure age, several types of surface applications can be utilized during the asphalt service life.

For new asphalt, it is recommended that you wait at least 90 days and up to 18 months before applying the least expensive sealer, a fog seal. If your surface remains intact, fog seals can be applied annually for several years. Other surface maintenance applications include slurry seal, seal coat, and chip seal, which are more costly and used with crack filling when the paving section has failed to a point where a fog seal is ineffective. 

In conclusion, a regular and inexpensive maintenance schedule is suitable for preserving asphalt surfaces and the underlying pavement section. When designed correctly, your pavement will last well beyond its engineered service life.