Need a book? Engineering books recommendations...

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

Re: Gas Tight Seal

[Subject Prev][Subject Next][Thread Prev][Thread Next]
I agree with your thoughts that you will essentially need to create an
expansion joint with a flexible sealant cap that will be air-tight.  ACI
504 provides details of typical joints.

I don't have my caulking literature anymore but there were a number of
silicone caulks that would be suitable for adhesion between old and new
concrete surfaces.  I think that you'll probably end up with a filler
material (it could probably double as the bearing pad you mentioned
originally) and a bond breaker.  Whenever I've called a caulk manufacturer
they have had a lot of data.  You should also know how much movement and
rotation that may occur at the joint for selecting the material as well as
sizing the joint.  A number of caulks have been qualified in the nuclear
industry for penetration sealants when subjected to differential pressures
after a steam line break.





"Randy Russ" <rruss(--nospam--at)eatel.net> on 10/22/98 07:58:47 PM

Please respond to seaint(--nospam--at)seaint.org

To:   seaint(--nospam--at)seaint.org
cc:    (bcc: James H Annett)
Subject:  Re: Gas Tight Seal




The deck will be cast against the wall as a cold joint (i.e. simply
connected). I have a good coating system for the new concrete, I am
concerned about gas escaping through the cold joint. The digester does
produce gases and therefore a pressure differential across the joint. The
purpose of the seal is for odor control.

I am considering notching the top of the existing concrete wall and
applying a flexible sealant. I am searching for a product or products to
use.

Randy Russ, P.E.

----------
> From: jannett(--nospam--at)gpu.com
> To: seaint(--nospam--at)seaint.org
> Subject: Re: Gas Tight Seal
> Date: Thursday, October 22, 1998 1:38 AM
>
>
> How will the slab edge will be placed against the top of the wall?  How
are
> you defining gas tight, e.g., is there a difference in pressure across
the
> seal and how much leakage is acceptable?
>
> If the differential pressure is significant and if the allowable leakage
is
> supposed to be small, it will be difficult to do this with only concrete.
> I've had enough trouble with air tight seals on steel doors & airlocks
with
> rubber gaskets.
>
>
>
>
>
>
> "Randy Russ" <rruss(--nospam--at)eatel.net> on 10/21/98 10:02:28 PM
>
> Please respond to seaint(--nospam--at)seaint.org
>
> To:   "Structural Chat" <seaint(--nospam--at)seaint.org>
> cc:    (bcc: James H Annett)
> Subject:  Gas Tight Seal
>
>
>
>
> I am putting a concrete roof on an existing wastewater digester. I am
using
> a center column for the roof and am simply resting the slab edge on the
top
> of the esisting wall on a bearing pad.
>
> I am concerned with gas escaping. Do I need to provide any type of gas
> tight seal or is the weight of the 18 inch roof slab enough.Has anyone
> encountered this situation?
>
> Randy Russ, P.E.
>
>
>
>
>
>
>
>
>
>