Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

RE: Lean concrete as structural fill?

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Jim,

ASTM has decided that this type of material is "Controlled Low Strength
Material"  The typical field description is "flowable fill."

Specified compressive strengths vary from 100 to 1000 psi.   If you ever
plan on excavating this material, use a lower strength.

There are usually several variants available from the local Concrete
providers.

As Bill stated, strength is not usually the big issue.  Flow, shrinkage, and
consolidation are.

FAA has a good reference spec on line in their ASW 600.  Also, try the
USACOE, I believe they have several references.

Hope this helps.

Arvel

-----Original Message-----
From: Scott, William N. [mailto:William.Scott(--nospam--at)veco.com]
Sent: Wednesday, July 06, 2005 2:42 PM
To: 'seaint(--nospam--at)seaint.org'
Subject: RE: Lean concrete as structural fill?


Jim,

Lean concrete backfill is commonly used to backfill excavations under
existing structures. The actual f'c is not too important. The density,
consolidation, and complete filling of the void is critical.

Bill

-----Original Message-----
From: Jim Wilson [mailto:wilsonengineers(--nospam--at)yahoo.com]
Sent: Wednesday, July 06, 2005 11:29 AM
To: seaint(--nospam--at)seaint.org
Subject: Lean concrete as structural fill?


We are working with a contractor who has asked to use
lean concrete as structural fill under footings and
slabs for a single story building.  Through google
searches, I've come up with matches to lean concrete,
cement bound material (CBM) and flowable backfill.
Are these all essentially the same product?  They
don't appear to be well defined in terms of material
properties, though I found one reference to 500psi
minimum strength.  The flowable fill I have worked
with in the past was 700psi. Also, these products are
only mentioned in the context as being used for
roadway sub-bases.  I'm guessing they are not commonly
used in building construction because they are
relatively costly compared to gravel backfills.

By comparison to regular gravels, this seems very
acceptable as structural fill, but I'm looking for a
second opinion.  And is there an appropriate spec or
even a product name to call this material for building
use?

Regards,
Jim Wilson, PE
Stroudbsurg, PA

******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
*
*   This email was sent to you via Structural Engineers
*   Association of Southern California (SEAOSC) server. To
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
*   send to the list is public domain and may be re-posted
*   without your permission. Make sure you visit our web
*   site at: http://www.seaint.org
******* ****** ****** ****** ******* ****** ****** ********

******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
*
*   This email was sent to you via Structural Engineers
*   Association of Southern California (SEAOSC) server. To
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
*   send to the list is public domain and may be re-posted
*   without your permission. Make sure you visit our web
*   site at: http://www.seaint.org
******* ****** ****** ****** ******* ****** ****** ********



******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
* 
*   This email was sent to you via Structural Engineers 
*   Association of Southern California (SEAOSC) server. To 
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you 
*   send to the list is public domain and may be re-posted 
*   without your permission. Make sure you visit our web 
*   site at: http://www.seaint.org 
******* ****** ****** ****** ******* ****** ****** ********