The Effects of Styrene-Butadiene-Styrene (SBS) Polymers on the Improvement of Mechanical Properties of Hot Mix Asphalt (HMA)

In recent decades, using polymers to improve bitumen properties is increasing. In 1960`s the copolymerization techniques developed and Styrene - Butadiene - Styrene (SBS), one of the most effective additives which has plastic and thermoplastic properties at the same time, has been offered in bitumen market. This polymer will improve the properties of bitumen both in high (FBP= 130c) and low (FBP=-38 c) temperatures, then it is practicable for all weather conditions and its performance will be satisfying in both conditions. In this research the effects of SBS polymer on bitumen and asphalt was studied. Past examinations shows that SBS polymer will decrease the Frass breaking point and lose weight of bitumen and also increase the softening point and penetration grade of it. SBS polymer also improves the properties of asphalt, including the increase of Marshall Resistance and flow of asphalt mixtures; but it has no considerable effect on specific gravity of asphalt; and at the same time decreases the optimal bitumen percentage of asphalt.