1- Department of Civil and Environmental Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
2- Department of Civil and Environmental Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran , phajikarimi@aut.ac.ir
3- Dept. of Research and Development, Pasargad Oil Company, Tehran, Iran
4- Dept. of Research and Development, Pasargad Oil Company, Abadan, Iran
Abstract: (15 Views)
Accurate analysis of bitumen behavior as a viscoelastic material and its natural phenomena such as aging are important issues in pavement engineering. Therefore, controlling the low and high temperature properties of bitumens is essential to prevent low temperature cracking and common high temperature distress in order to provide proper service throughout the pavement life. In this study, the aging phenomenon and its effects on the mechanical properties of bitumens were simulated using the Superpave method, namely the RTFOT method for short-term aging and the PAV method for long-term aging. In order to investigate the effect of repeated PAV cycles on the properties of bitumens, three types of bitumen with different penetration degrees of 40-50 (PG70-16), 60-70 (PG64-22) and 85-100 (PG58-28) were selected and three samples of each were subjected to one to three PAV aging times. The beam shear rheometer (BBR) test was performed at three temperatures from 0 to -12°C and the dynamic shear rheometer (DSR) at seven temperatures from 46 to 82°C. Based on the results obtained, the high temperature performance of the bitumens increased by a maximum of three grades and their low temperature performance increased by a maximum of two grades. In other words, the grading of the triple bitumens, after three times of PAV, became 82-4, 82-10, and 70-16, respectively. Also, the relationship between the high temperature performance properties of the aged bitumens and their chemical changes at different times of aging was investigated and their changes were examined to show the correlation between these properties. The results showed that the high temperature viscoelastic properties and the chemical aging index of the different bitumens had a strong linear relationship with a coefficient of determination (R2) of more than 0.9.
Article Type:
Original Research |
Subject:
Roads and Transportation Received: 2024/07/22 | Accepted: 2024/11/20