چكيده به لاتين
Commercial TPE polymers offer desirable features in improving performance characteristics of neat asphalt binders at high, medium and low in-service temperatures. However, higher cost of synthetic TPEs such as styrene-butadiene-styrene (SBS), hindered widespread utilization of these materials in asphalt modification practice significantly. The purpose of this study is to investigate the effectiveness of utilizing three combinations of recycled PET and crumb rubber as TPE polymers to improve rutting and fatigue damage resistance of neat asphalt binders. The physical, rheological and storage stability properties of two unmodified and six modified binders were evaluated using penetration, softening point, rotational viscosity, dynamic shear rheometer, multiple stress creep and recovery and linear amplitude sweep tests. According to conventional binder tests, these polymers improves penetration and softening point while reducing temperature susceptibility of asphalt binders. However, binders’ viscosity increase to some extent. From rheological results obtained, the proposed polymer formulations can enhance binder stiffness and phase angle at high and medium temperatures, thereby binder resistance against permanent deformation and fatigue cracking shifts to higher and lower temperatures, respectively. Moreover, much more enhancement at high in-service temperatures could be reached by using higher PET percentage. At medium temperatures and high frequencies, polymer network formation contributes to greater resistance to fatigue damage as a result of reduction in complex modulus and phase angle. On the basis of storage stability test results, the high percentage of modifiers slightly increases polymer separation potential at high temperatures of asphalt mixture construction and the instability increases with higher amount of PET in polymer combination.
