Thursday, March 12, 2009

RE: Green Point Rated Concrete

ACI 318 also allows higher percentages if not exposed to deicing chemicals.
 
I routinely allow 25% fly ash in concrete mixes.  I'd be cautious using up to 50% fly ash but 50% slag is not uncommon.
 
Bill Sherman
CH2M HILL / DEN
720-286-2792
 

From: Tom.Hunt@fluor.com [mailto:Tom.Hunt@fluor.com]
Sent: Thursday, March 12, 2009 5:03 PM
To: seaint@seaint.org
Subject: Re: Green Point Rated Concrete


Tom,

I don't know about residential construction but for structural concrete ACI 318 allows fly ash up to 25 percent, blast slag up to 50 percent, silica fume up to 10 percent, and a mixture of these up to 50%.  See ACI 318-05 Section 4.2.3.

Thomas Hunt, S.E.
Fluor

"Tom Monti" <tomm@mhengineering.com>
03/12/2009 03:45 PM
Please respond to seaint
To
<seaint@seaint.org>
cc
Subject
Green Point Rated Concrete



List members,
 
To reduce the use of virgin materials and to recycle, Build it Green is recommending that 25-50% of the portland cement used for residential foundation concrete be replaced by flyash or slag. What are your thoughts and implications on this recommendation? What percentage would you replace without concerns?
 
I am reluctant to replace any cement without some feedback.
 
Thank you for your input
 
Thomas L. Monti, PE
MH Engineering Co.
16075 Vineyard Blvd.
Morgan Hill, CA 95037
(408) 779-7381 x228
(408) 226-5712 FAX 
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