Application of rubber dust in modified asphalts for SMA mixtures

Abstract

Abstract: The experimental investigation described in the paper refers to the properties of asphalts and asphalt mixtures with addition of rubber wastes. The influence of rubber additive, on rheological properties, viscosity, penetration, softening point of the asphalts were analyzed. An innovative technique based on the combined use of microscopic observations was developed. Tests results were compared to the conventional asphalts. Positive effects of modification were recorded. Two types of asphalt mixtures were prepared on the same mineral aggregate. For reference a Stone Matrix Asphalt (SMA) was used with polymer modified (PM) asphalt 45/80-55. Then the Stone Matrix Asphalt was prepared on the base of asphalt-rubber (45/80-55 AR). These materials were tested on rutting and water and frost resistant. The results indicated that the SMA mixtures prepared on the base of rubber modified asphalt exhibit greater resistance to permanent deformation, at elevated temperatures and greater water and frost resistance than the conventional SMA mixtures. Tests results were compared to technical requirements for SMA layers. It was found that this type of asphalt mixture can be successfully used in road surfaces, especially exposed to freezing. Keywords: Asphalt mixture; SMA mixture; rubber asphalt; Recycling; Dynamic viscosity.