Investigation of the Physical and Molecular Properties of Asphalt Binders Processed with Used Motor Oils

Abstract

In this work we investigated the performance aspects of addition of used motor oils (UMO) to neat and crumb rubber modified asphalts (CRMA) and related that to the change of molecular size distribution of modified asphalt's fractions; asphaltenes, saturates, naphthene aromatics, and polar aromatics. Based on the results of temperature sweep viscoelastic tests, addition of crumb rubber modifier (CRM) alone or with UMO results in the formation of internal network within the modified asphalt. Based on the results of short and long term aged asphalts, the utilization of combination of UMO and CRM enhanced the aging behavior of asphalt. Bending beam rheometer was utilized to investigate the low temperature behavior of UMO modified asphalts. Based on those tests, the utilization of the UMO and CRM enhanced the low temperature properties of asphalts. Based on the results of the asphalt separation tests and the Gel Permeation Chromatography (GPC) analysis, it was found that saturates and naphthene aromatics are the two asphalt fractions that have similar molecular size fractions as those of UMO. However, UMO only shifts the molecular sizes of saturates after interaction with asphalt. Results also show that polar aromatics pose higher molecular size structures than UMO.

Balancing the Performance and Environmental Concerns of Used Motor Oil as Rejuvenator in Asphalt Mixes

“…Abdelrahman et al [1] investigated the effect of adding UMO on the macro (|G*| and δ) and micromechanical properties (hardness and elastic modulus) of neat and crumb rubber modified asphalt (CRMA) binders. It was found that using UMO deteriorated the properties of the neat asphalt binders [1,2]. Furthermore, it was noticed that asphalt binders modified with crumb rubber (CRM) only enhanced rutting resistance, increasing the value of (|G*|/sinδ).…”

“…Furthermore, it was noticed that asphalt binders modified with crumb rubber (CRM) only enhanced rutting resistance, increasing the value of (|G*|/sinδ). The best enhancement in fatigue cracking resistance, the |G*|.sinδ parameter, was achieved using asphalt binder modified with both UMO and CRM when compared with samples modified by UMO or CRM only [2]. The same research group [2] investigated the effect of mixing UMO on asphalt binder's fractions: asphaltenes, saturates, naphthene aromatics, and polar aromatics.…”

“…The best enhancement in fatigue cracking resistance, the |G*|.sinδ parameter, was achieved using asphalt binder modified with both UMO and CRM when compared with samples modified by UMO or CRM only [2]. The same research group [2] investigated the effect of mixing UMO on asphalt binder's fractions: asphaltenes, saturates, naphthene aromatics, and polar aromatics. It was found that for UMO, most components are located in the category of saturates.…”

“…Moreover, it was observed that asphaltene fraction increased with the addition of CRM and UMO regardless of the interaction time or temperature. For an intermediate interaction temperature of 190 • C, it was noted that adding CRM and UMO slightly increased the saturates fraction [2]. A bending beam rheometer (BBR) was utilized to observe the effect of using both CRM and UMO on the modification of asphalt binder to resist low-temperature (thermal) cracking.…”

“…A bending beam rheometer (BBR) was utilized to observe the effect of using both CRM and UMO on the modification of asphalt binder to resist low-temperature (thermal) cracking. It was noted that the best resistance to thermal cracking was achieved by using asphalt binder modified by both UMO and CRM [2]. Gel permeation chromatography was used to evaluate the molecular size distribution in the asphalt binder's fractions as a result of their interaction with CRM and UMO.…”