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Re: RE: Flowable fill

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Harold, would cellular concrete fall under this ACI classification also?

edward arrington

>>> SpragueHO(--nospam--at) 05/15/00 11:08AM >>>

This is a pretty good slide show on flowable fill. 

The ACI committee 229 is on CLSM (controlled low strength materials).

The mixes I have seen go in at about 140 pcf wet density.  And cure to about
130 pcf.  They can support the weight of a man in about 4 hours.

There are light weight flowable fills also.  I have used them with a wet
density of 30 pcf and an oven dry density of 21 pcf.

In answer to your questions:
1.	It is a fluid.
2.	140 pcf for normal CLSM.  30 pcf for the real light weight stuff.
3.	It depends on how much subsidence you can tolerate see the ACI 229
report.  The only lift height limitations that I know of are based on
hydrostatic pressure.

Harold Sprague

> -----Original Message-----
> From:	Pat Ebner [SMTP:PEbner(--nospam--at)] 
> Sent:	Monday, May 15, 2000 12:04 PM
> To:	seaint(--nospam--at) 
> Subject:	Flowable fill
> We have a below grade tunnel which the contractor wants to backfill
> against using flowable fill.  The walls of the tunnel are reinforced
> concrete and are 14' max. tall.  I have several questions regarding the
> pressure the flowable fill will generate against the walls.
> 1)   Is the pressure a fluid pressure or is it dependant on the rate of
> placement?
> 2)   If it is a fluid pressure, what would be a typical unit weight for
> the fill?
> 3)   Should the fill be placed in multiple lifts?  If so, how much time
> should there be between the pouring of the lifts and how deep should the
> lifts be?
> Any other input is welcome.
> Thank you.
> Patrick Ebner, P.E.