چكيده به لاتين
In asphalt mixture, bitumen as a binder plays a very important role and despiteof its low value relative to other components in the mixture, it has significant contribution on asphalt behaviour under different loads. so that bitume properties improvement helps considerabley to promote quality of asphalt mixture. Modified pavement with polymer shows better performance against rutting, thermal cracking and fatigue. So that, bitumen which are modified by polymers, especially ones that modified with elastomer-thermoplastic polymer, are produced. The aim of this paper is to evaluate the effect of EVA polymer as an additive to enhance the performance of bitumen against rutting. 60-70 bitumen and two kind of EVA polymer, 18%VA and 28%VA is used in this work. Two types of experiments, DSR and RV is implemented on samples. To blend bitumen and polymer, high shear mixer is used. G*, δ parameters and G*/sinδ ratio are extracted from DSR test and V,VTS parameters from RV test. The results of DSR test show that adding polymer inceases bitumen stiffness, enhances elastic behavior and makes the bitumen stronger against permanent deformation and rutting. Also results of RV test show that polymer increases bitumen viscosity and decreases temperature susceptibility. In 58°C and 64°C, for all samples, either base bitumen and modified one with EVA polymer, there is not any problem against rutting performance, in all percents(because for all of them G*/sinδ ratio is more than 1Kpa). The results show that, the sample with 2% polymer, don’t have significant difference with pure bitumen, but samples with 4% and 6% polymer showed better performance against rutting. Also, the results illustrates that in samples with EVA polymer, the 18%VA samples show better performance than 28%VA one.
