×
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

Slab on grade, crushed agg. base
3

Slab on grade, crushed agg. base

Slab on grade, crushed agg. base

(OP)
I have an issue with compaction requirements for a crush aggregate base, we currently have no requirement.  I have not been able to find information on whether there is even a compaction requirement for crush aggregate or aggregate under a slab on grade.  I have looked in ACI 302 but it was no help.  Does any have information on what should be used?  Also what does everyone else use?

RE: Slab on grade, crushed agg. base

"Crushed stone specs" search in google gives something. This is a first one

http://www.3b3d.com/html/Geotechnical%20engineering%20other%20topics/20080413/7756.html

I have seen heavy rollers compacting 60 to 80 cm say 7cm and lower typical crushed stone. I would love to remember that the compaction was made in layers, but it is not in my mind. A colleague ran the show, was for just 6 floors or so above, and placed under a structural mat of akin thickness.

RE: Slab on grade, crushed agg. base

Our local DOT (Illinois)compaction requirements include in-situ dry density to be 95% of the dry density that is determined in laboratory testing.  This is for PCC Pavement, so YMMV.  You might check your states DOT Specifications book, as it likely spells out the compaction requirements for aggregate subbase.

RE: Slab on grade, crushed agg. base

sandman21....crushed aggregate, unless graded to achieve a graded aggregate base material, is not a material in which compaction specifications can be readily defined.  We generally use a laboratory moisture-density relationship (Proctor test) to define the laboratory condition, then compact to achieve some percentage of that in the field (95%, 98%, 100%).

Using a gap-graded aggregate layer beneath a floor slab requires that you compact it, but you have little or no measure of compaction.  Plate compactors don't work well for this, and "jumping jacks" are out of the question.  A small roller, vibratory or static will work to achieve uniformity.

RE: Slab on grade, crushed agg. base

(OP)
Thank you for the help

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