Effect of recycled engine oil bottoms on the ductile failure properties of straight and polymer-modified asphalt cements

- REOB can improve the AASHTO M320 grade span at reduced cost to producers.
- REOB decreases ductile failure properties which makes binders prone to failure.
- SB polymers improve strain tolerance and thus improve cracking performance.
- REOB addition to SB-modified binders significantly deteriorates performance.
- RAP addition to SB/REOB-modified binders further worsens cracking performance.

This paper presents a study on the effects of recycled engine oil bottoms (REOB) on ductile failure properties of asphalt cements. Binders were tested according to regular AASHTO M320 as well as double-edge-notched tension (DENT) test protocols. The DENT test determines essential work of failure (we, a measure of strength and toughness) and critical crack tip opening displacement (CTOD, a measure of strain tolerance). REOB was found to increase the AASHTO M320 grade span but worsen we and/or CTOD. Straight and polymer-modified binders were studied, with and without REOB and reclaimed asphalt pavement (RAP) binder, and significant decreases in we and CTOD were found, pointing to reduced cracking performance.