HMA Surface Characteristics Related to Ride, Texture, Friction, Noise, Durability

More and more attention has been paid recently to hot mix asphalt pavement surface characteristics. In addition to structural capacity and durability, it is now desirable to design pavements to meet noise, texture, friction, and ride requirements. Noise (both interior and roadside) is at the forefront of the minds of both pavement designers and the traveling public.

The traditional way to reduce noise for nearby residents and businesses has been to build noise walls. Besides being large and unsightly, noise walls can also be quite expensive. Innovative pavement surfaces have recently been developed as an alternative to building noise walls. The type of wearing course plays a major role in determining the surface characteristics of a pavement. Several options that can provide lower noise levels than conventional dense-graded pavements include stone matrix asphalt (SMA), open graded friction course (OGFC), porous HMA, 4.75-mm Superpave mixes, and NovaChip. In general, pavements with smaller maximum aggregate size, open gradation, and negative macrotexture produce less noise.

SMA and OGFC pavements have been used extensively in the southern United States with great success. However, far fewer states in cold climates have used these open-textured mixes. As a result little is know about the performance of open-textured mixes in cold climates. There is a fear that over the harsh winter the pavement will disintegrate due to sand and salt operations, freeze-thaw action, snow plowing operations, and other typical cold climate factors. There is a need to conduct a controlled experiment in a northern state like Minnesota to determine the durability and performance of a pavement built for certain surface characteristics. MnROAD offers an experimental site where open-texture mixes can be installed and monitored in a cold climate environment.