High Temperature Behavior of Asphalt Mixture with Bitumen Modified by Polyphosphoric Acid Polymers and Rubber Powder

The main purpose of this study was to determine the effect of adding polyphosphoric acid (PPA) and rubber powder (CR) on the modification of bitumen properties and also to evaluate the asphalt mixture made of modified bitumen. In addition to the usual tests of new bitumen, a variety of standard tests of strength and modulus of elasticity were performed on the asphalt mixture at high temperatures. The results showed that the addition of PPA improved the performance of bitumen at high temperatures and also reduced the effects of aging in the sample and the addition of rubber powder also improved the performance in the entire operating temperature range of bitumen. The combination of these two additives has also succeeded in reducing the bitumen sensitivity to temperature and aging and also increasing the bitumen resistance to common damages at high temperatures. The combination of these two additives was also able to improve the performance grading of bitumen (PG) to ۴ categories without having much effect on the performance of bitumen at different temperatures. In order to investigate the microstructural changes in the samples after modification with rubber powder and polyphosphoric acid, the morphology of the samples was performed by scanning electron microscopy and the uniformity and integrity of the modifiers with bitumen was revealed. Marshall Resistance in modified and average samples increased by ۱۵% compared to unmodified samples and also the modulus of resistance in modified samples increased by ۲۴% on average compared to control samples.

کلیدواژه ها:

modified bitumen ، Polyphosphoric acid ، Rubber powder ، High Temperature Behavior ، Asphalt mix