The performance evaluation of extracted asphalt binder from dry process produced rubber modified asphalt mixture

Limited research studied the influence of rubber on asphalt binder in the dry process rubberized asphalt mixture. By using the extraction procedure, the asphalt binder interacted with rubber could be obtained and assessed. The goal of the research is to evaluate the accurate characteristics of asphalt binder from dry process rubberized asphalt mixture and determine the interacted rubber percentage in dry process rubberized asphalt mixture. Four extracted and two laboratory prepared asphalt binders were compared. The rheological performance, creep and recovery, and low temperature characteristics of different were evaluated with the dynamic shear rheology, multiple stress creep and recovery, and asphalt binder cracking device tests, respectively. The rubber modification and aged binder from the RAP enhanced the high temperature characteristics of the asphalt binder. Rubber modification increased the elastic property and deformation resistance of the asphalt binder and decreased the stress sensitivity of the asphalt binder. The coupling effect of aged asphalt binder and rubber addition enhanced the permanent deformation resistance of the asphalt binder to sustain heavy stress load. The aged binder from RAP deteriorated the low temperature characteristics of the extracted asphalt binder. The base asphalt binder with rubber had a better ability to dissipate the stress in the asphalt binder due to the decrease in temperature. The interacted rubber percentage was estimated by comparing the rutting parameter and percent recovery, and the estimation results based on the DSR and MSCR test had a good correlation. The interacted rubber percentage in the two types of rubber modified mixtures are 61.9% and 57.4%, respectively.