SUPERPAVE Digest 311

Topics covered in this issue include:

4) Scraping RTFO bottles; AASHTO T240 vs. PP1-98

by

5) Re: Scraping RTFO bottles; AASHTO T240 vs. PP1-98

by "Kenneth Hobson" <>

  • To:
  • Subject: Scraping RTFO bottles; AASHTO T240 vs. PP1-98
  • From:
  • Date: Tue, 1 Feb 2000 14:55:43 -0600

Could somebody explain something to me? In AASHTO T240, section 7.7 and note 4

of that, explains that scraping is part of the procedure. Mainly to insure that

all or most (90%) of the material is retrieved from the bottle. Now, in PP1-98,

section 10.2 (towards the end), it states that scraping is not currently allowed

in T240.

Isn't the most important thing here, getting at least 90% of the residue out of

the bottle? If you can do that without scraping, is that OK?

Are there new test methods out there that I'm unaware of?

Thanks for your help!!!!

  • To: "''" <
  • Subject: RE: Scraping RTFO bottles; AASHTO T240 vs. PP1-98
  • From: "Dempsey, Steve (SPDE)" <
  • Date: Tue, 1 Feb 2000 18:12:47 -0800

We got gigged to on our AMRL inspection. We now scrape regardless. What's

really ridiculous is seeing a tech trying to get 8 bottles scraped out in 5

minutes and still adhere to the requirement of closing the door and starting

the carriage and air with each bottle. Want to see a real show wait till we

have to pull the rods out of the bottle and scrape all within 5 minutes.

SUPERPAVE Digest 312

Topics covered in this issue include:

2) RE: Scraping RTFO bottles; AASHTO T240 vs. PP1-98

by

  • To:
  • Subject: RE: Scraping RTFO bottles; AASHTO T240 vs. PP1-98
  • From:
  • Date: Wed, 2 Feb 2000 08:38:26 -0600

Steve, it is good to know that others out there are concerned about this too. I

see no reason to scrap normally unless it is for PP1. The original AC specs did

not require scrapping. By scrapping and using the old AC specs one does not get

the same material. Now, add in the rods and who knows how much that affects the

material grading as compared to the "old way".

Of course we will adhere to all requirements. I guess it is the ole production

versus research syndrome that gets me sometimes. When one adds in the new DTT

requirements, the work load increases by almost two.

We will be reporting to the ETG on the new MP1a specification.

Kenneth Hobson

Bituminous Branch OKDOT

SUPERPAVE Digest 313

Topics covered in this issue include:

3) Re:Scrapping RTFO bottles/ Rods in the bottles

by

  • To:
  • Subject: Re:Scrapping RTFO bottles/ Rods in the bottles
  • From:
  • Date: Fri, 4 Feb 2000 22:03:35 EST

Scrapping: With modified binders it is an absolute must when trying to

recovery 90% of the residue. Even with "neat" asphalts most would be hard

pressed to get 90% out of the glassware without scrapping. I often weigh

bottles back to check and it is difficult to obtain 90% even with scrapping.

Possibly the development of a standard scrapping tool that incorporates

features to gather residue from all the surfaces would help make a messy

procedure more efficient.

RTFO Rods: I do not like this idea. I believe the use of rods for testing

modified binders in ASSHTO T240 will allow poor quality modified binders

passing results on subsequent tests. Additionally, I do not think the use of

a steel rod provides better replication of the mixing, laydown, and

compaction processes. It will provide better test results for the binder

supplier but it won't provide better performance for the pavement.