عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Polymer application for the improvement and modification of the bitumen used in roads surfaces has expanded in recent decades. The roads engineers and constructors, therefore, have used the modified bitumen in asphalts helping in this way to increase roads and pavements service life and improving the durability of the roads and asphalts. The bitumen used in asphalt mixture constitutes only a low percentage of the weight of this mixture (between 4% and 6%), but even this small amount has a significant effect on asphalt performance. The polymers that are mostly used in promoting the bitumen specifications are polymer modifiers including: styrenebutadiene- styrene (SBS), as well as similar polymers such as styrene-butadiene-rubber (SBR), ethylene-vinylacetate (EVA) and polyethylene (PE). Polymers as the most important family of bitumen modifiers are added to bitumen to improve bitumen performance and to increase its effectiveness. Among the existing polymers, SBS is considered as the best bitumen modifier. In this research, SBS as one of the elastomer-thermoplast modifiers was added in different weights (2%-5%) to bitumen 60/70 in Isfahan Refinery and its effect on asphalt properties were investigated. Adding this polymer to bitumen improves the Marshall stability of sample asphalt, flow, module of rupture and asphalt content voids. However, it has a minor effect on asphalt special weight. Adding SBS would also lead to asphalt fatigue life.