Characterising the modifying efficiency of polyphosphoric acid to bitumens with different oil sources

ABSTRACT

To explore the properties and mechanism of different polyphosphoric acid (PPA)-modified bitumen, this research selected three bitumens with different oil sources and two PPAs with different relative H₃PO₄ contents (which are 105%, 115%, namely 105 and 115 grade PPA, respectively). A succession of tests and analyses was conducted to explore the performance of the PPA-modified bitumens. The physical performance test results show that PPA improves the high-temperature performance of the bitumens, and it has different modification effects on the three bitumens. When PPA reacted with the bitumen that has a higher content of polar components, the performance variation of the bitumen was higher than the other two kinds of bitumens. Furthermore, the 115-grade PPA seemed to have a better modified efficiency than that of the 105-grade PPA due to the longer molecular chain length. This also leads to the entanglement of molecular chains of PPA-modified bitumen was more significant with the 115-grade PPA. Therefore, the 115-grade PPA-modified bitumen shows a large asphaltene agglomeration in the AFM diagram.

KEYWORDS:

• Bitumen
• polyphosphoric acid
• conventional performance
• rheological properties
• modification mechanism

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The research was funded by the National Science Foundation of Guangxi Province (2021GXNSFAA220134) and the Science and Technology Plan Project of Guangxi (grant number Guike AD21238001)