- 期刊
Oxidative Aging of Asphalt Cements from an Ontario Pavement Trial
並列摘要
This paper documents and discusses a rheological and spectroscopic investigation of the oxidative aging in asphalt cements from a 2003 northern Ontario pavement trial. Seven asphalt cements were aged according to standard methodology (rolling thin film oven test (RTFOT) and pressure aging vessel test (PAV)), as thin films at temperatures of 45, 65, and 85 ℃ and standard pressure (thin film oven test (TFOT)), and under modified PAV conditions (extended time of 40 hours). It was found that the current RTFOT/PAV protocol provided insufficient aging for the poor performing asphalt cements. Infrared analysis of the TFOT-aged samples for the formation of carbonyl groups could largely explain the performance ranking in service. The only significant outlier was modified with polymer and waste engine oil residue. Rheological investigations of the recovered and the TFOT-aged residues were able to show that such materials likely suffer from early gel formation. These findings illustrate the need for improved asphalt cement aging protocols. A preliminary example is provided that shows how simply doubling the PAV aging time to 40 hours can produce materials that more closely replicate those aged for 5-6 years in a northern Ontario climate. It was further confirmed that both chemical and physical hardening tendencies are closely correlated, likely because they involve similar asphalt constituents.