Fatigue Performance of Re-Refined Engine Oil Bottom–Modified Asphalt: Laboratory Study

Abstract

Re-refined engine oil bottom (REOB), one of several products obtained from refining recovered engine oil, has been used in the asphalt industry since the 1980s. Generally, REOBs are used to help soften the base asphalt binder and are commonly used from 3% to 10% by weight to achieve desired low temperature asphalt binder properties. Recently, blame for poor cracking performance in a number of Canadian and northern U.S. pavement sections has been laid on the use of REOBs. This issue has prompted state agencies in the northeast United States to ban its use, without necessarily understanding how REOB affects asphalt binder and mixture performance. A research effort was conducted to evaluate the laboratory performance of asphalt binders and mixtures modified with REOB. Performance grading, master stiffness curves, the double-edge notch tension test (DENT), and black space analysis were conducted on the asphalt binders at different levels of laboratory aging. The research study showed that while being able to achieve softer asphalt binder grades in accordance with AASHTO R29, the addition of REOB accelerated the age-hardening effects in the asphalt binder, with higher levels of age hardening occurring at higher REOB dosage rates. The study also indicated that while the stiffness properties at low temperatures were not affected by REOB, the relaxation properties were highly affected. The black space analysis, using the Glover–Rowe approach, and the DENT test showed promise in identifying the age-hardening effects and correlated well with mixture fatigue cracking.

Sustainability Assessment of Green Asphalt Mixtures: A Review

“…Recently, there has been a growing interest in blending VTB with asphalt binder to improve the low-temperature performance of HMA. The introduction of VTB softens the asphalt binders and helps to improve their intermediate and low-temperature properties [172,173]. Concerns about high-temperature performance and aging susceptibility due to oil modification exist.…”

“…It can be observed that such high percentages of substitution results in a significant detrimental decrease in high temperature (HT) PG. There are some other types of bottoms, such as re-refined engine oil bottom (REOB) and re-refined heavy vacuum distillation bottoms (RHVDB) that have similar negative and positive influences on HT and LT grades, respectively [173,174]. In order to mitigate the negative effect of VTB on high temperature performance, the combination of CRM and VTB was evaluated and found that any combination of 15% and 20% CRM with 50% and 70% VTB can preserve the HT grade of the neat binder (PG 58-22) while improving the LT of it as well [175].…”

Laboratory Performance of Asphalt Mixtures Containing Re-Refined Engine Oil Bottoms Modified Asphalt Binders

“…Transportation Research Record 2672 (28) analysis and interpretation of results: Mohammad, You, Cooper, draft manuscript preparation: Mohammad, You, Shi. All authors reviewed the results and approved the final version of the manuscript.…”

“…Transportation Research Record 2672 (28) where, J c = critical strain energy release rate (kJ/m 2 ), b = sample thickness (m), a = notch depth (m), U = strain energy to failure (kJ), and dU/da = change of strain energy with notch depth (kJ/m). Figure 3 presents the critical strain energy (J c…”

“…Intermediate-temperature fatigue cracking of short-term and long-term aged asphalt mixtures was studied by Bennert et al ( 28 ). Three fatigue tests, including overlay tester (OT), a semi-circular bend (SCB) test, and a flexural beam fatigue test, were conducted with two types of asphalt binder (PG 64-22 and PG 58-28) and various REOB contents from two sources.…”