×
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

sand vs clay vs crusher dust

sand vs clay vs crusher dust

sand vs clay vs crusher dust

(OP)
I am building a 60 x 100 structural steel building.  The building will have a 2' x 2' reinforced concrete foundation.  Concrete blocks will will bring the building up to grade.  The height of the blocks will be about 2' in the back and  4' in the front.  My question is what would be the best material to use to fill with under the slab.  Choices are between sand, crusher dust and clay.  I can get the crusher dust the cheapest because of a friend at the rock quarry, but is it suitable for compaction.

RE: sand vs clay vs crusher dust

Sand is the better option.  It is the least reactive to moisture of the three choices.  Crusher dust and clay are more difficult to compact.

RE: sand vs clay vs crusher dust

(OP)
Thanks Ron for the info.  It's interesting that the guys in the office at the Quarry are saying the dust is a better choice.  Maybe they are wanting to get rid of dust instead of sand.

RE: sand vs clay vs crusher dust

Ahh... schoolteacher that would be because it depends on the sand and the quarry dust you have available. Clay in general forget it. But without any further details I agree with Ron, go for the sand.

RE: sand vs clay vs crusher dust

st...ask them for a gradation on the crusher dust.  If all of the particles pass a No. 16 sieve and it has more than 10 percent passing a No. 200 sieve, use the sand.  

The term "dust" implies rock flour, which is a very fine material, not suitable alone for fill or compaction.

RE: sand vs clay vs crusher dust

(OP)
They are supposed to be faxing me that info.  I will post it as soon as i recieve it.  Thanks  

RE: sand vs clay vs crusher dust

Gradations do not tell the whole story. Depending on the crushing equipment and the type of rock, you could end up with a lot of flat fines that distort the gradation and compact differently. That will not compact weel and can shift later.

Also, if the rock is limestone, the fines can be cubic and there is an amount of cementing ability in the fine fines that can develop later.

Dick

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

RE: sand vs clay vs crusher dust

CM....there was no indication by the OP that the crusher dust was calcareous.  Very fine calcareous materials are bad actors as well.  Yes, there is some cementation that occurs from hydration of the carbonates; however, getting compaction in calcareous materials with a high fines content is difficult at best.

Gradation doesn't tell the whole story, as you noted, but it's a good starting point.

RE: sand vs clay vs crusher dust

Also many types of sand out there.

In some locations "quarry dust" is used as a term for crushed rock fines.

RE: sand vs clay vs crusher dust

Too many shades of "sand" and also "crusher dust."  Either supplier should be able to give gradations and moisture-density relations (i.e., Standard or Modified Proctor).  Problem with some sands is that they realize their best compaction at close to saturation moisture content.  Crusher dust (some) can be very good for subgrade/subbase below a concrete slab on grade.  You can get some good CBR numbers from crusher dust, which correlates to good subgrade modulus values.

No, I'm not taking anything away from Ron and others in their recommendation for sand, I'm just saying crusher dust (what we call No. 10 screenings) can be pretty well graded and very dense when compacted.  Around Virginia, much of the No. 10 screenings are the by-product from processing #57 open-graded aggregate.  There's a lot of granular material below the No. 10 screen.

f-d

¡papá gordo ain't no madre flaca!

RE: sand vs clay vs crusher dust

f-d....I agree, just that we don't know what they are calling "crusher dust".  Gradation curve necessary.

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