Although most of us drive and park on asphalt everyday, asphalt is still somewhat of a mystery to many people. Following are a few of the more common questions that we receive about asphalt.
Q: What exactly is asphalt?
A: Asphalt pavement is usually 95% aggregate, which could be stone, sand, or gravel, and 5% asphalt cement as a binder. The binder is a product of oil refining and acts to glue the aggregates together. The aggregate and asphalt are heated, combined with the recycled material and mixed together. Then we load the hot pavement material into trucks and take it out to the site.
Q: How widely is asphalt used?
A: About 94% of the nation’s roads and highways are surfaced with asphalt.
Q: Can asphalt be recycled?
A: Asphalt pavement is the most recycled material in America. The industry recycles more than 70 million tons of asphalt pavements every year, more than the combined total of glass, paper, plastic, and aluminum combined.
Q: Doesn’t concrete last longer than asphalt?
A: The New Jersey Turnpike provides a good example of the life cycle of an asphalt pavement. That pavement has been in use for 50 years under very heavy traffic, and the chief engineer says he thinks it can last another 50 years. That’s what we call the Perpetual Pavement. Asphalt pavements can last a lifetime because it’s possible to maintain them just with milling and overlays, and the deeper portion of the pavement structure remains sound. If you design a pavement correctly for the amount of traffic it will have to stand up to, you can have actually a permanent pavement structure. With our new heavy-duty surface pavements, it is possible for overlays to last more than 15 to 20 years. It just makes sense to design a pavement so that it will serve you long-term, not so that it has to be replaced at a given point in time.
Q: Is asphalt more expensive than concrete?
A: The initial cost of asphalt pavement construction is usually less than concrete. In addition to initial construction costs, there have been numerous studies within the U.S. and Europe which have shown that asphalt pavements generally have a lower life cycle cost.
Q: What are the main benefits of asphalt?
- It cost less to construct and maintain asphalt than alternative pavements.
- Asphalt construction projects can be completed more quickly than alternative pavements.
- Asphalt pavements are the smoothest pavements
- Asphalt pavements generate less noise than alternative pavements.
- The contrast of the black pavement and white lines make it easier for motorists to understand driving and parking regulations – making asphalt a safer pavement.
- Properly designed, constructed and maintained asphalt pavements last significantly longer than alternative pavements.
- Asphalt is recyclable.
Q: How can I protect my asphalt?
A: There are a number of steps that you can take to prolong the life of your asphalt and maximize your investment.
- Seal within six months after installing new asphalt.
- Seal every two to three years thereafter.
- Regularly check for longitudinal or transverse cracking and have cracks sealed.
- Patch low areas before cracking develops.
- Minimize irrigation run-off onto your asphalt.
- Work with a quality asphalt maintenance company like OliverMahon to develop an asphalt maintenance plan that specifically meets your needs and budget.
Q: What causes asphalt to fail?
A: Assuming that the initial asphalt pavement was designed and constructed properly, the primary cause of failure is the penetration of water into the asphalt base. Asphalt failure often begins with the oxidation of an untreated pavement surface which causes the asphalt to become dry and brittle. The top layer of fine particles erodes, exposing the larger aggregate and leading to small cracks on the surface. These cracks will grow if left untreated, allowing water to penetrate to the base of the pavement. When water enters the base of the pavement, the base material shifts and settles leading to further cracking and a depression in the surface. As water pools in the depressed area, the asphalt further deteriorates and becomes unstable. When the pavement reaches this stage, removal and replacement of the old asphalt is often the only remedy.
Q: Does the rising price of oil impact asphalt prices?
A: Yes, the price of asphalt is directly linked to crude oil prices, which fluctuate when supplies vary.
Q: How long do I have to keep cars off of a lot or street that has just been worked on?
A: In most parking lots, you should plan to keep cars off of a newly paved or sealed surface for 24 hours in order to allow the product time to dry and cure. Certain road and street work may allow traffic to return sooner depending on the specific mix and conditions.