It’s no secret that oil prices are steadily increasing, and as the price of oil rises, so, too, does the price of asphalt pavements. What’s less well known is that the inherent costs of asphalt paving are typically much higher than they may seem.

In terms of the initial costs alone, there was a long-held belief that asphalt was cheaper than concrete pavements. With oil prices now at more than $100 per barrel – and, at this writing, even spiking to $106 per barrel, the stark reality is the costs of asphalt are not only high, but are also becoming more volatile.

No End in Sight?
State and local agencies are feeling the effects of the price volatility that is more apparent now than any time in recent memory. The Fort Worth Star-Telegram reported that for the Texas Department of Transportation, the “price of asphalt hot mix rose 89 percent between 2001 and 2007. For the 326 million gallons [of liquid asphalt] the department used in the past fiscal year, that’s an added cost of $378 million in one year just for asphalt.” In sharp contrast, the article noted that concrete prices have increased only 29 percent for the same period.

This example underscores what agencies and contractors are experiencing nationwide. The cost of asphalt oil, or PG-58, has increased nationally more than 236 percent since 1996, according to reports by Engineering News-Record. At the end of 2007, the average national price of PG-58 was $281 per ton.

Many states allow price escalators for asphalt and fuel, but not for any other materials, including steel, wood or cement. With an asphalt escalator, an agency actually pays more to a contractor for asphalt materials at the time of construction than the price quoted when the project is awarded.

Agencies are taking on an added financial risk because they cannot predict how much more they will be paying during construction than at the time of the bid. Less money may be available for roadwork if the true ownership costs for asphalt pavements are not considered. Actual costs of public projects are not reported accurately because escalators are rarely reported publicly.

The cost of asphalt escalators is resulting in agencies paying much higher prices for asphalt than originally expected. A year ago, reports were surfacing that some states with asphalt escalators were paying three to four times more for asphalt because of price volatility. At present, there are cases where escalators are resulting in costs that are as much as 1,400 percent higher than the asphalt prices in original bids.

Hidden Costs of Asphalt
Another significant cost is the true costs of placing pavements, not only in terms of the raw materials, but also the time and ancillary costs of fuel. Placing a concrete pavement is about three times faster than comparable asphalt.

The reason for this is that asphalt is typically placed in layers, which must then be compacted repeatedly. Concrete pavements, by contrast, are typically placed in one layer.   

Fresh concrete is typically transported to work zones in concrete trucks and then fed directly to a slipform paver, which places the continuous layer at a specified thickness. A recent study measured the placement of asphalt and concrete pavements at seven different locations, all with similar designs. The result of the study was a 319 percent faster rate for concrete than asphalt. The average rate was 7,876 square yards per production day for concrete pavement vs. only 2,647 square yards per production day for asphalt.

To put this in broader perspective, consider that a four-lane primary highway from New York to Los Angeles would span 2,800 miles. In this example, it would take 95 years for a single asphalt paving crew to reach Los Angeles, which is more than three times longer than what paving with concrete would take.

In addition to the time to place the pavement, there are even more costs that often are overlooked. For example, concrete pavements do not require the regularly scheduled maintenance and repairs that asphalt pavements do. Asphalt pavements require regular maintenance every two to four years to correct rutting, shoving, cracking, potholes and other deficiencies.

The repair and maintenance cycles can be even shorter, especially in Midwestern and Northeastern regions, where capricious weather patterns can wreak havoc on asphalt pavements. ABC News reported in late February that in Chicago, “the city’s command center can barely keep up with the potholes – eight times as many as last year.

“In 2007, Chicago citizens called in 1,000 complaints,” the  report stated. “So far this winter, they’ve called in 8,000 complaints, with the current season among the snowiest and coldest in a decade.”

The problem stems from the freeze-thaw cycles, which are particularly problematic on asphalt, which is a flexible pavement. “The pavement tends to flex and crack,” the report states. It also says the pavement “crumbles” and gets “bounced out” of cracks.

An Ongoing List
There are even more costs connected to the placement, maintenance, repair, and eventual reconstruction of asphalt pavements than concrete pavements. Asphalt pavements require a tremendous amount of energy – such as fossil fuels – to heat materials to the requisite 325 F at the production plant. Next, the asphalt is delivered to the construction site, where asphalt pavers and compaction rollers use even more fossil fuel to place the road in 12-foot wide multiple layers, often with three or more layers for highways.  

Generally speaking, asphalt requires about 8,981 gallons per mile (GPM) for production and 1,737 GPM for hauling and placement. Compare this to 548 GPM for production of concrete and 1,369 GPM for placement.

So, from production to placement, asphalt requires at least 5.5 times more energy than concrete. And that’s only the beginning. Factoring in the repeated maintenance and repair cycles, as well as the eventual reconstruction of asphalt pavements every eight to 14 years, the fuel consumption and costs are even more dramatic.

 In contrast, concrete pavements typically only require replacement every 30 to 40 years. The Federal Highway Administration (FHWA) estimates that approximately 500 million tons of asphalt is placed in the U.S. transportation network every year. This means 1.5 billion gallons of diesel fuel are consumed to build asphalt roads, using the FHWA’s usage factor of 2.9 gallons of diesel fuel per ton for asphalt construction.   

If the 500 million tons of asphalt were replaced with concrete, it would require only 17 percent of that amount of diesel fuel. This would result in annual savings of 1.2 billion gallons of fossil fuels, almost half of the 2.5 billion gallon average of all the refined low or ultra-low sulfur diesel fuel imported into the United States between 2003 and 2007.

For roadbuilders and agencies that have long been using asphalt, there are even more compelling reasons to consider concrete now. There are reports that refineries are becoming increasingly sophisticated at extracting value from a barrel of oil. As the process efficiencies improve, more of the barrel will be used for high-end products such as gasoline and lubricants, leaving less asphalt, which historically has been considered the bottom-of-the-barrel. This could portend increasingly tight supplies of asphalt, and along with that, even higher prices.

With oil prices now topping $100 per barrel – and with no end in sight to pricing volatility – concrete is increasingly the right choice for anyone concerned with the bottom line and the best return on investment.

Robert Rodden is the director of technical services at the American Concrete Pavement Association. He can be reached at This e-mail address is being protected from spam bots, you need JavaScript enabled to view it or by calling 847-966-2272.