Use of tung oil as a rejuvenating agent in aged asphalt: Laboratory evaluations

摘要

One of the most effective measures to utilize abundant reclaimed asphalt pavement (RAP) materials, generated by the maintenance and reconstruction of asphalt pavements, is to employ rejuvenating agents. This study recognized tung oil as a rejuvenating agent and four different tung oils (2%, 4%, 6%, 8%, by weight.) blended with aged asphalts were carried out to assess the effect of tung oil on the performance and characteristic functional groups of Pen70 aged asphalt and SBS modified aged asphalt. Desired contents of tung oil were decided preliminarily by conventional property tests involving penetration, softening point, ductility, and rotational viscosity. Afterward, dynamic shear rheometer (DSR) tests including temperature sweep and frequency sweep and bending beam rheometer (BBR) tests were conducted, and Fourier transform infrared spectroscopy (MR) tests were implemented to analyze rheological properties and characteristic functional groups of original asphalt, aged asphalt and rejuvenated asphalt, respectively. Experimental results indicated that the addition of tung oil could enormously ameliorate the flexibility of aged asphalt, and suitable contents of tung oil can ensure the high-temperature performances of rejuvenated asphalts. Meanwhile, rejuvenated asphalt performed a better low-temperature cracking resistance than that of virgin asphalt from the test results of BBR. The stiffness of rejuvenated asphalts concluded by master curves is even higher than their corresponding virgin asphalts due to suffering aging, meaning they have lower temperature sensitivity. Also, Carbonyl and sulfoxide index of the Pen70 aged asphalt could be effectively abated by mixing with tung oil, but the existence of tung oil may interfere the test results of FTIR of SBS modified aged asphalt. (C) 2019 Elsevier Ltd. All rights reserved.