The Impact of Crumb-Rubber on the Mechanical Characteristics of Modified Asphalt Mixture

By following up on the effect of rubber, which has recently been widely used as a direct additive to the asphalt binder or to the concrete mix as a percentage of the weight of the aggregate. The success of the effect of this type of admixture on improving the modified asphalt binder in addition to the modified concrete mix has been investigated. As it was noted the importance of following the asphalt properties due to the increasing use of crumb rubber modifiers in asphalt mixtures, there is a more position to check their rheological and physical properties comprehensively. In general, the performance of the asphalt rubber binder is affected by the rubber crumb content and mixing conditions. This research used 40/50 asphalt grade and Crumb Rubber additives with contents (5, 10, 15, and 20%). The main objectives of this study were to investigate the physical and rheological properties of rubber-modified asphalt binder and mixture. These purposes were achieved by testing HMA samples using the Marshall test approach to determine (Marshall stability and flow and void properties) and measuring the retained Marshall stability and DSR and Viscosity test. Sample testing showed that when recycled rubber was used as modifiers for asphalt mixes, the mixture became more stable, had a higher bulk specific gravity, and had less flow value and air voids. This infers that using recycled rubber can enhance the rutting resistance of bituminous mix.