The Impact of Diamond Grind Pavement Resurfacing on PM-10 Emissions

Since 2003, the Arizona Department of Transportation (ADOT) has used asphalt rubber asphaltic concrete friction course (often referred to as “rubberized asphalt” or “quiet pavement”) on Phoenix regional freeways to reduce noise. As the rubberized asphalt overlay nears the end of its service life, ADOT and the Maricopa Association of Governments (MAG), which is responsible for planning future improvements to Phoenix-region freeways, are determining the most cost-effective approach to resurfacing the freeways. The agencies are considering whether to continue using rubberized asphalt or to remove it, expose the underlying concrete surface, and then diamond grind the surface. Diamond grinding removes a thin surface layer of concrete using closely spaced diamond-saw blades and aims to create a smooth, level surface. ADOT and MAG are piloting diamond-grinding on segments of State Loop 101 to assess life cycle cost, ride quality, and public acceptance of diamond-ground concrete. In 2006, Arizona State University completed a limited study for ADOT that examined the impact of rubberized asphalt on tire wear compared with concrete surface. However, the study did not investigate the emission rates of particulates due to tire wear on diamond-ground concrete. PM-10 refers to particulate matter that is 10 micrometers or less in diameter. ADOT and MAG would like to know if diamond-ground concrete has the potential to reduce PM-10 emissions similar to rubberized asphalt. The study would measure PM-10 emissions along freeway segments on which diamond grinding has been and is scheduled to be performed, and would forecast the impact on PM-10 emissions and the Phoenix region.