Effect of Rosin Modification on Bitumen and Hot Mix Asphalt

This study investigated the effect of rosin on modification of bitumen and hot mix asphalt performance. Generally, natural resin is obtained from the body of tree naturally and fractionated and rosin which is distilled and volatile terpenes have been removed from natural resin. It is light yellow and transparent material. Bitumen is modified with rosin in 2%, 4%, 6% and 8% by weight of bitumen in mixture. Characteristics of bitumen after modification is determined with bitumen tests (rotational viscometer, penetration, softening point, ductility, elastic recovery, and penetration index). In this study, bitumen was graded according to Performance Grading (PG) system and PG 64-22 bitumen was used. Also, stiffness modulus was calculated by empirical model. Optimum bitumen contents of modified bitumen for all percentages were determined. After optimum bitumen percentage is determined hot mix asphalt samples were prepared with these percentages according to SuperpaveTM mix design. After all, tensile strength and moisture susceptibility is determined with Indirect Tensile Strength test. The results showed that 2% rosin modified bitumen showed good results among the other modifications. It has highest moisture resistance. And the indirect tensile strength results of rosin modified Hot Mix Asphalt (HMA) were higher than the reference sample. Also, 6% rosin modified bitumen showed best stiffness modulus and elastic modulus according to the empirical model