Traffic noise is an environmental issue and is even called “pollution,” and for good reason. It might not belch soot into the air or contaminate water sources, but in urban areas it’s critical to take it into account so people can live comfortably (without suffocating in the thunderous noise coming in from roads outside).
The combination tire speed and pavement type is what determines traffic noise. Tire-pavement noise is made worse with rolling, slipping, or dragging tires against pavement, especially when vehicles are moving at a higher speed. Other factors that affect tire-pavement noise including the type of vehicle, temperature, weather, the age of the pavement surface, and the surface type itself.
While most of these factors can’t be controlled, the one factor you have control over is the pavement surface type. You’re able (and empowered) to strategically choose a surface to reduce noise. Using traffic noise on a typical highway as our baseline (which ranges from 55 to 80 decibels of volume), we analyzed the different types of pavement and their noise levels to help you choose the best pavement for your project.
Open Graded Friction Course
Open-graded friction course (OGFC) is the quietest pavement surface, producing even less noise than conventional HMA and PCC surfaces. Its noise production is estimated to 69-77 dB(A).
OGFC uses small holes (or “air voids”) in the pavement to provide a sound-absorbing negative texture. OGFC can be made with conventional liquid asphalt or with polymer-modified asphalt, including rubberized asphalt. Rubberized OGFC typically uses finely- ground rubber that’s been recycled from tires in order to change the asphalt binder in the mixture.
Because they have air voids, these OGFC varieties differ from a more conventional, densely-graded hot mix asphalt (HMA) in several key ways. For one, OGFC air voids start from 10 to 22% and usually see a little decrease over pavement life. And because of those air voids, the surface is also referred to as “porous asphalt.” These air voids absorb a large amount of noise generated by the friction of the tires and the surface itself.
Hot Mix Asphalt
Hot mix asphalt (HMA) can generate a noise production equivalent to 72-79.5 dB(A). HMA is made by heating aggregates to decrease the viscosity of the binding agents and make the whole mix more fluid. Then, it’s dried to remove any moisture.
HMA air void structure generally ranges from 6 to 7%. Anything above 10% gives the asphalt a shorter life. On the other hand, even if hot mix asphalt isn’t the quietest, it is considered as the most durable type of pavement—which is why it’s generally used for highways and high roads. Asphalt is weather resistant and can efficiently stand up to wind, heat, freezes, and floods. Its heat absorption, in fact, has the capacity to melt snow and ice faster than any other type of paving material.
Stone Matrix Asphalt
Stone matrix asphalt (SMA) is popular because of its durability and resistance. It’s considered to be a great option for high-traffic areas, including highways and interstates, as well as busy intersections. This pavement type is a gap-graded HMA originally developed in Europe.
Since this material allows less elasticity but greater resistance, it’s noisier than the two mentioned above. However, used in the right situations, it’s more cost-effective and has greater resistance over the years. Even the quietest pavement type will get noisy when it gets filled with cracks and potholes.
Portland Cement Concrete
Portland cement concrete (PCC) is, once again, a degree less “quiet” than the pavement types above since it generates approximately 76-85 dB(A) in traffic noise. It’s commonly made from materials like limestone, shells, and chalk or marl combined with shale, clay, slate, blast furnace slag, silica sand, or iron ore.
The difference in noise levels between HMA and PCC surfaces is a little more dramatic when PCC is grooved or tined, too (which is commonly done to improve skid resistance). However, if the surface is diamond ground, it becomes equal to HMA as far as noise reduction.
Additionally, Portland cement concrete is more economical than other pavement materials.
Composite is not usually used to pave roads on its own. It’s actually a mix of asphalt and concrete and it is used as a repair material for pavement maintenance. It’s often seen as an asphalt overlay for damaged areas, such as to fill cracks and potholes.
Depending on the location of your project, always take the road noise into consideration when choosing your pavement type. Other priorities like resistance, durability, elasticity, and aesthetic will help you make your final decision.
Though traffic noise is produced by many different factors, the pavement type has a big impact on the end noise perceived by those who live or work in the zone. Without a doubt, OGFC is the best option for areas where traffic noise reduction is of the utmost importance. However, its longevity is less than other paving options, usually needing to be repaired or repaved every 9-10 years.
Hot mix asphalt is another popular go-to since it still helps reduce traffic noise and usually lasts 12-15 years before requiring repair.
Which pavement type makes sense for your roads or parking lot? Get a free quote from Reliable Paving today.