×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Class F vs class C flyash

Class F vs class C flyash

Class F vs class C flyash

(OP)
Which one is the more common type of flyash for general residential and smaller commercial projects (sog, foundation wall, basement wall etc)? When to use one class vs the other?

Thanks.

RE: Class F vs class C flyash

I'm not sure you get the choice. In Eastern area, where bituminous coals are used, you get class C, in the West, where they burn anthracite, you get Class F. I might have the coals mixed up, but I think in general, you get Class C in the East, Class F in the west.
I think Class F combines more completely with the other cementatious materials.
Ask your local batch plants what they use.

RE: Class F vs class C flyash

They (the local producer) will use what is available and common in the area and not stock a separate product for a single project, which would require a new set of silos and mix designs (and testing). Most supplies of fly ash are under long term supply contracts with major distributors and cement companies. The concrete supplier is the end user and vaules a steady, guaranteed supply of known materials.

It is a local situation and depends on availability and freight costs.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

RE: Class F vs class C flyash

Yes, rely on the local supplier to guide you. Particularly on small projects, you don't want to invent a new mix. Use a mix they already have experience in producing. If there are performance or appearance parameters, then performance spec the concrete (strength, aggregate size if it is critical to placement due to bar spacing, and anything particular about appearance or use), rather than WCM ratio, amounts of CM, slump, etc. unless required by Code.

On large projects, where new mixes are critical to function, the development and testing costs are worth while. Not so much on small projects.

RE: Class F vs class C flyash

(OP)
Thanks all.

Jed, yeah I heard somewhere that east of Mississippi is class C and west is class F.

I'll contact 2 or 3 major suppliers in the area to get a more definite answer.

RE: Class F vs class C flyash

it makes very little difference which one used, except in the mix design which is usually handled by the supplier. The benefits are about the same to the designer and contractor.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources