RE: [GBlist] cistern and harmful additives in concrete

["Ralph Bicknese" <ralph.bicknese@christnerinc.com>]

Hi Sacie:

I saw the artice in Fine Homebuilding last night but did not have time to
read it all.

In clarification I am suggesting that concrete will crack eventually. The
cracks may be little more than hairline cracks and will not necessarily
cause a tank to leak or to leak much.  But the possibility also exists that
cracks will emerge big enough to cause significant leakage or worse yet,
contamination of the water from outside the tank (if below grade). For
example, concrete basements very frequently leak unless specific precautions
are taken (such as sloping grade away, using drainage tile, sufficient
granular backfill, proper reinforcement in the foundation wall to accomodate
structural loads and to reduce shrinkage cracking) and a waterproofing
system verses a damp proofing system).

A "dampproofing" or "waterproofing" additive in the concrete mix may help
reduce the threat of moisure migrating through the concrte but it will not
bridge any cracks, hairline or otherwise, that eventually occur.  I am
suggesting a liner, whether fluid applied or a sheet membrane, would give
you long lasting durability and sanitation.  You would not have to reapply
this "every few years".

Cheers,
Ralph

-----Original Message-----
From: Sacie H Lambertson [mailto:dlambert@grasshoppernet.com]
Sent: Wednesday, September 26, 2001 9:18 PM
To: greenbuilding@crest.org
Subject: [GBlist] cistern and harmful additives in concrete


Can someone tell me if it is harmful to put an air entrainment (sp?)
product in the concrete mix for a potable water cistern?  Sacie Lambertson
	Any comments on Ralph's thought that adding a waterproofing additive is
rather useless since the cistern is going to crack anyway?  Frankly, the
idea of getting down every few years into a couple of large concrete tanks
that are only 5 feet tall to seal with Thoroseal, is most unappealing.

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This greenbuilding dialogue is sponsored by REPP/CREST, creator of
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______________________________________________________________________
This greenbuilding dialogue is sponsored by REPP/CREST, creator of
Solstice http://www.crest.org, and BuildingGreen, Inc., publisher of
Environmental Building News and GreenSpec http://www.BuildingGreen.com
______________________________________________________________________