Straight Run Asphalt 1

[ponderer]

We produce a penetration grade Asphalt from a Vacuum Distillation Unit(without Air Blowing) in our refinery.

The penetration of our Asphalt is 50~100.

Our customer claim that although our product meet the penetration specification of Asphalt, the Aging test show that our product has a higher viscosity change(2.0 vs. 1.7 by other refinery) with TFOT(Thin Film Oven Test).

My question is:

Is the Aging test the normal specification of Asphalt?
or only penetration is normally requested by end user?
(Our customer use the Asphalt for highway paving)

 

[25362]

A higher viscosity change after TFOT or RTFOT indicates more sensitivity to aging conditions. The aging is due to oxidation i.e., the creation of more polar molecules, resulting in a stiffer internal structure, and to the volatilization of some lower molecular weight hydrocarbons.

Assuming TFOT and viscosity tests are carried out on both products with a relative high degree of repeatability and reproducibility, the differing results between refiners selling equal non-oxidized penetration grades, with a more or less equal thermal history, and equal vacuum fractionation efficiency, may stem from operating on different crude oils.

Yes, many asphaltic bitumen users request a laboratory-accelerated aging test such as TFOT including, not only loss of mass, but also the measuring of the change in, at least, one residual property such as viscosity, ductility or penetration.

One commercial request for bids on bitumen I found while googleing around:

http://www.voy.com/92822/48.html

You may see that the potential client is asking for a series of properties on the residue after TFOT.