In addition to being smooth, durable, safe, and quiet, asphalt is the most versatile pavement material. Pavement structures can be designed to handle any load, from passenger cars to heavy trucks. Surface mixes can be customized to absorb noise, to reduce splash and spray during rainstorms, and even to help treat rain water.
Busy commercial airports have main runways surfaced with Asphalt. Asphalt is also used extensively on runways at general aviation airports. Asphalt’s speed of construction makes it an ideal choice for rehabilitation of busy aviation facilities.
At racetracks, asphalt pavements provide smooth driving surfaces combined with the excellent traction demanded by professional stock car racing. Of the 33 NASCAR race tracks across the country, 31 have asphalt surfaces. Of the 88 race tracks listed for the NASCAR Short Track series, 66 are asphalt, 21 are dirt or clay, and 1 is concrete.
Whether on the road, in a parking lot, or at an airport, asphalt pavements add up to the best value for the taxpayer dollar, with the lowest life cycle cost and the highest residual value.
Mix Type Selection
Pavement type selection processes are used by pavement authorities such as state highway agencies to identify the most beneficial type of pavement structure for a given set of traffic, soils, climate, and other factors. They may be as simplistic as specifying a certain type of pavement on the basis of traffic level, or they may be as complicated as assigning weighting factors to more than a dozen characteristics and evaluating the outcome through a scoring system. Whatever process is used, it should be a rational and explainable methodology in which the effects of different variables on decision making may be determined. Information used to develop the process should reflect documented historical performance and cost records.
The 1993 AASHTO Guide for the Design of Pavement Structures, published by the American Association of State Highway and Transportation Officials, outlines the considerations for pavement type selection in its Appendix B. The principal factors to be considered include traffic, soils characteristics, weather, construction considerations, recycling, and cost comparison. The secondary factors include performance of similar pavements in the area, adjacent existing pavements, conservation of materials and energy, and availability of local materials, among other issues.
The Asphalt Pavement Alliance has developed a position paper in order to discuss the primary considerations in pavement type selection as presented in the AASHTO Guide in detail, and to present the advantages available from Hot Mix Asphalt pavements in each of these. Additional considerations include the issue of tire-pavement noise generation, ride quality, and safety, and the advantages asphalt offers in these characteristics.
Perpetual Pavement combines the well-documented smoothness and safety advantages of asphalt with an advanced, multi-layer paving design process, that with routine maintenance, extends the useful life of a roadway. Pavements designed and constructed in accordance with the Perpetual Pavement concept will last, and last, and last.
How it works
Perpetual Pavements use multiple layers of durable asphalt to produce a safe, smooth, long-lasting road. The pavement design begins with a strong, yet flexible bottom layer that resists tensile strain caused by traffic, and thus stops cracks from forming in the bottom of the pavement. A strong intermediate layer completes the permanent structural portion, and a final layer of rut-resistant HMA yields a surface that lasts many years before scheduled restoration. A Perpetual Pavement provides a durable, safe, smooth, long-lasting roadway without expensive, time-consuming, traffic-disrupting reconstruction or major repair.
When scheduled surface restoration is performed, Perpetual Pavements can be maintained easily and cost-effectively without removing the road structure for reconstruction, saving time and money while keeping motorists happy.
Asphalt is recyclable, providing further cost savings and environmental benefits.
Asphalt has a proven safety record as a driving surface, offering stronger visual contrast with center stripes and other markings. Additional advantages can include reduced noise, reduced splash and spray, and greater skid resistance.
Porous asphalt pavements offer developers and planners a new tool in their toolbox for managing storm water. These pavements, used mostly for parking lots, allow water to drain through the pavement surface into a stone recharge bed and infiltrate into the soils below the pavement. Such pavements have been proving their worth since the mid-1970s, and recent changes in storm water regulations have prompted many consulting engineers and public works officials to seek information about them.
In the world today, noise has become one of the most pervasive forms of environmental pollution. Noise is everywhere. It affects our lives at home, at work, and at play. Wherever people live there is noise. Noise, by definition, is any unwanted or excessive sound. It can be a nuisance, interfering with sleep, work, or recreation.
There is one type of noise that can be effectively treated at its source: road noise. By paving roads and highways with asphalt, noise experienced both inside and outside homes and businesses can be significantly reduced.
Research in the U.S. and Europe shows that resurfacing a noisy road with stone-matrix asphalt (SMA) or open-graded friction course (OGFC) mix will reduce highway noise by 3 to 5 dB(A) or more. To the average person, this reduction is the same as doubling the distance between the source of the noise and their location.
When comparing the noise reduction that is possible by choosing asphalt pavement, we see how much more practical pavement surface selection is than construction of noise barrier walls.
Warm-mix asphalt is the generic name of technologies that allow the producers of hot-mix asphalt pavement material to lower the temperatures at which the material is mixed and placed on the road. Reductions of 50 to 100 degrees Fahrenheit have been documented. Such drastic reductions have the obvious benefits of cutting fuel consumption and decreasing the production of greenhouse gases.