Investigation of mechanical properties of modified mixtures with recycled asphalt addition

In this thesis, the mechanical properties of modified mixtures prepared with recycled asphalt were investigated. In the study, firstly, the recycled asphalt pavement (RAP) material was separated into aged bitumen and aggregate. Then, the obtained aged bitumen was mixed with three different rejuvenators: biorap (4%, 8% and 12%), Hydrolene (8% and 10%) and Rapiol (4%, 6% and 8%) under the same conditions and it has been tried to be rejuvenated so that it has the same physical properties as B 50/70 pure bitumen. The physical properties of all binders subjected to the rejuvenation process were tried to be determined by softening point, penetration and viscosity experiments and the most appropriate ratio was determined for each rejuvenator. Then, using B 50/70 pure bitumen and new aggregate, hot mix samples were prepared according to the Marshall design method and the optimum bitumen content was determined. Based on this determined content, hot mix samples were prepared by using various ratios of RAP (10%, 20%, 30% and 40%) with rejuvenator. In order to determine the aging effect on the prepared samples, some of the samples were also subjected to aging in the laboratory environment. Both unaged and aged hot mix samples obtained were subjected to Marshall stability and flow, indirect tensile strength (ITS), moisture damage resistance, indirect tensile stiffness modulus (ITSM), indirect tensile fatigue and dynamic creep tests. Although the use of RAP at the maximum rate of 25% in the binder courseis allowed in the Highways Technical Specifications, the usability of RAP in the wearing course was investigated in this study. The name of the Biyorap rejuvenator used in the study was later changed to "Progiline Eco-T recycled asphalt" and was used for the first time in academic studies. According to the binder results obtained, binders prepared with 12% biorap, 10% Hydrolene and 8% Rapiol rejuvenating bitumen showed the same physical properties as B 50/70 bitumen. According to the mixture results, the performance properties of the mixtures with 10% RAP additives were almost the same compared to the hot mixture sample prepared with pure bitumen (B 50/70).