Need a book? Engineering books recommendations...

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

Re: W/C ratio, was:purposely permeable c

[Subject Prev][Subject Next][Thread Prev][Thread Next]
The slab assembly is 5" concrete over 2" clean sand cushion, 10mil vapor
barrier, 4" crushed rock over engineered fill (over re-worked expansive
Jeff Smith
-----Original Message-----
From: Roger Turk <73527.1356(--nospam--at)>
To: seaoc(--nospam--at) <seaoc(--nospam--at)>
Date: Tuesday, June 09, 1998 8:53 AM
Subject: Re: W/C ratio, was:purposely permeable c

>Have you considered a vapor barrier?  If the purpose is to prevent moisture
>migration thru the slab, I think that a more positive method than a low w/c
>should be used.
>I have seen effloresence on vinyl tile here in *dry* Tucson.
>A. Roger Turk, P.E.(Structural)
>Tucson, Arizona
>Jeff Smith wrote:
>. > The soils report says...
>. >
>. > " to further reduce the potential for moisture to migrate through the
>. > slabs-on-grade as a vapor, as well as to reduce concrete shrinkage, we
>. > recommend that the concrete mix specified for the slab on grade floors
>. > have a water/cement ratio of .45 or less."
>. >
>. > This is a non-profit low income housing project, in many places there
>. > sheet vinyl flooring. The site soils are expansive and the top foot or
>. > is disturbed, so the site work includes removing several feet of soil,
>. > bringing in new soil and raising the elevation of the entire site due
>. > some civil/road/grading issues. I have been told that certain
>. > and plasticizers yield unpredictable finish results because the top
>. > hydrates at a different rate than the center. Given the same cost, I
>. > would prefer adding cement rather then admixtures.
>. >
>. > Jeff Smith
>. >