Performance Evaluation of Moisture Sensitivity of Asphalt Mixture Containing Polymer Blends

One of the important goals of the researchers is reduce the damage of asphalt pavement in order to the increses of safety of road users. The moisture is known as one of the environmental asphalt failure factor which attracted researcher’s attention. The modification would results in failure reduction and maintenance cost. SBS polymer is one of the most widely used polymers to improve the asphalt functional properties, but importing this polymer causes it much costly. So, economic assessments lead engineers to use alternative materials. In this study, in order to improve the properties of binder, a combination of two inexpensive domestic (made by Iran) polymer is used to achieve a compound similar to Thermoplastic elastomers polymer. In this regard, polymer blends of SBR and PP with same amount has been mixed. Then, this combination of polymers has been added to bitumen with ratios of 3, 4 and 5% of weight. On the other side, in order to compare performances, SBS polymer was also used in ratios of 4 and 5% in bitumen of asphalt mixtures. Moreover, in order to provide polymer stability in modified bitumen, namoclay has been added 1.5% of binder weight. Results of Marshall stability test, indirect tensile test, resilient modulus and Texas boiling test has been compared. The results has been shown equal and better performance of mixture contains 5% polymer blends in comparison with mixture contains 5 % SBS; and indicates a 20% increase in moisture resistance compared to the unmodified sample.