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RE: Concrete Exposed to Sulfates

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See below for responses.

Harold Sprague


-----Original Message-----
From: TwoWids(--nospam--at)aol.com [mailto:TwoWids(--nospam--at)aol.com]
Sent: Thursday, February 11, 1999 8:38 PM
To: seaint(--nospam--at)seaint.org
Subject: Concrete Exposed to Sulfates


I would be interested in hearing from others how they are applying or
interpreting UBC Sec. 1904.3 and Table 19A-3 in regards to sulfates in the
soil.  There are some issues regarding foundation failures that I am
reviewing
that may or may not have been caused by applying these sections to the
design.
Here are some scenarios:

	1.  If sulfates are known to exist,  do you call out both the
water-cement ratio and the concrete strength per T-19-A3?
**** Yes ******

	2.  If the required concrete strength per the Table is greater than
the
design strength, which may very well be the case, do you require special
inspection to verify?
***** Your specified strength should be at least that required in the table.

How do you verify the water-cement ratio?
***** It should be on the mix design submittal sheet and is generally
implicitly verified by the delivery ticket.  I don't know of any way to test
this in the field.

	3.  If the foundation system is not required to be
designed/engineererd, such
as a conventional framing foundation, would the sulfate exposure
requirements
of Chapter 19 be applied?  
***** Yes

Section 1802 seems to require all concrete
foundations must conform to Chapter 19.

	4.  If you have sulfates and you design/engineer a portion of a
foundation
(and provide the strength and water-cement ratio for that portion) would you
also provide the same for adjacent non-engineered footings?
**** Yes

	5.  What do you tell the owner about the cost of all this testing?  
**** Tell him that it is required.

What do
you tell the contractor when he can't pump or work the .45 water-cement
ratio
concrete?
**** A mix with mid range and/or high range water reducers can be designed
to be either pumped in a line pump or overhead pumped.

Thanks for you input...Steve W.