چكيده به لاتين
Reclaimed asphalt pavement (RAP) produced from repairing and maintaining asphalt pavement layers is one of the waste materials which has bad effects on the environment. Determining the binder content of reclaimed asphalt, additive dosages, type, and its economic efficiency are the most important topics in producing new asphalt. Different additives such as rejuvenators, softer binders, and polymer modified binders have been used to recover the chemical and rheological properties of the RAP.
In this research, firstly, reclaimed binder extracted from RAP, then its chemical and rheological properties were investigated and compared with the control binder. In the next step, a softer binder (a P/G of 85/100), a 7/2% oil rejuvenator, and polybutadiene rubber were blended with different RAP contents (15, 25, 30, 50, and 100%). Chromatography (SARA fractionation test), furious transform infrared spectroscopy, and atomic force microscope were conducted on the samples. For evaluating rheological properties, dynamic shear rheometer (DSR), bending beam rheometer (BBR), and multiple stress & creep recovery (MSCR) tests were leveraged. Besides for asphalt mixture samples, wheel track and semi-circular beam (SCB) tests were conducted.
Results showed that asphaltene is the most important fraction of the binder. Softer binder blended with 50% RAP content showed the best performance. While in 100% RAP content, the rejuvenated binder showed better performance. Despite a very low glass transition temperature of PBR (-98), the sampled modified by PBR didn’t show a low-temperature improvement. Moreover, some strong relationships between rut depth and MSCR test parameters (Jnr and R %), SCB (fracture energy), and BBR test results were obtained.
