Book examines many details involving REOB/VTAE in paving

IS235_REOB.inddThe Asphalt Institute released a new 89-page publication this month that provides information on the use of re-refined engine oil bottoms (REOB) also known as vacuum tower asphalt extender (VTAE) in asphalt paving.

This free publication is entitled “IS-235 State-Of-The-Knowledge, The Use of REOB/VTAE In Asphalt” and was produced by the Asphalt Institute’s REOB/VTAE task force, made up of Asphalt Institute (AI) member company representatives, AI staff engineers and a representative from the Federal Highway Administration.

The book provides a comprehensive review of available information on the modification of paving grade asphalt binders with REOB or VTAE. Combining all the pertinent information in one place was the goal of the authors.

Asphalt Institute Director of Research and Laboratory Services R. Michael Anderson announced the release of IS-235 at the AASHTO (American Association of State Highway and Transportation Officials) Subcommittee on Materials annual meeting in Greenville, South Carolina on Thursday, August 4th.

“The book carefully defines REOB/VTAE as the non-distillable residuum from a vacuum tower in a used oil re-refinery,” said Anderson.

REOB/VTAE is used as a blending agent to soften binders. The demand for softer binder grades has grown in recent years due to higher levels of RAP (reclaimed asphalt pavements) and RAS (recycled asphalt shingles) being used in mixtures.

IS-235 details the background of REOB/VTAE, all health, safety and environmental considerations plus alternate tests and aging protocols for characterizing physical properties of asphalt binders. There is also an extensive review of 26 previously published papers on the subject as well as a frequently asked questions section.

The book is offered as a free PDF download at or as a free eBook at