Compound modification of asphalt mixtures for low-noise, low-emission and durability purposes

Abstract

Asphalt pavements are constructed widely all over the world because of various advantages, such as superior engineering performance, comfortable riding surface, the short maintenance time, to some extent, and alleviate the traffic noise. The utilization of different asphalt pavement has different strength, however, also has its limitations. High temperature needed when producing and constructing asphalt layers generates fumes and odors. Such emissions not only pollute the environment, but also pose health risks to the workers. In addition, the increasing volume of vehicular traffic on the roads also aggravates concerns of road pavement noise. Modifiers are introduced into the asphalt mixture to help make the asphalt a better performance in optimizing the air emissions, low-noise, and the durability properties. This study aims to assess different modified asphalt mixtures with focus particularly on the mechanical properties, acoustical emissions, and air pollutant emissions. Within the constraints of available equipment in the laboratory and construction sites for different pavement surfaces, limited but well-designed laboratory tests and site monitoring works were conducted. This study shows that the addition of modifiers, such as polymer and crumb rubber, can help improve the mechanical quality and low noise performances of the pavement but need higher working temperatures, which severely exaggerates the fume and odor issues as well as the concern of health. The warm mix additives, such as Sasobit®, mixed with the asphalt mixture can lower the working temperatures and thus reduce the air and odor emissions. The Gap-graded asphalt pavement with a smaller aggregate size has performed well in the mechanical and low-noise performances. With the modification by the Sasobit®, its particulate matters and volatile organic compound pollutants can be significantly reduced.