Big Green: "greener" concrete

[VanGeem, Martha]

Some rules of thumb:
 
Specs generally limit flatwork exposed to deicer salts to a maximum of
25% fly ash for durability reasons.
 
You can use recycled concrete for !00% of the subbase, and the coarse
aggregate, but generally the fine aggregate should be virgin. 
 
Whether you use your proposed mix or the rules of thumb, it is best to
test the mix to make sure it produces quality concrete. 
 

Martha G. VanGeem, PE (Illinois), MBA, LEED Accredited Professional
Principal Engineer & Manager, Building Science and Sustainability
Direct 847-972-3156
Cell 847-736-4366
Fax 847-965-5416
mvangeem at CTLGroup.com <mailto:mvangeem at CTLGroup.com> 

CTLGroup
Building Knowledge. Delivering Results.
5400 Old Orchard Road
Skokie, IL 60077-1030
www.CTLGroup.com 

 

________________________________

From: biggreen-bounces at lists.biggreen.org
[mailto:biggreen-bounces at lists.biggreen.org] On Behalf Of Lisa Goodwin
Robbins
Sent: Monday, July 07, 2008 8:26 AM
To: Big Green
Subject: Re: Big Green: "greener" concrete



For those of us who are not structural engineers, the July 2008 issue of
The Construction Specifier has an introductory level article about
supplementary cementitious materials (SCM), like slag cement, fly ash,
and silica fume.  The article references ACI 318 for recommended levels
of SCMs and notes that different concrete design conditions may lead to
different SCM levels.  50% fly ash may be too high for concrete in
contact with de-icing chemicals.

-- 
Lisa J. Goodwin Robbins, RA, CCS, LEED ap
Kalin Associates Inc.
1121 Washington Street
Newton, MA  02465
Tel:  617-964-5477
Fax:  617-964-5788
www.kalinassociates.com



________________________________

From: Peter Reppe <peterr at solarc-ae.net>
Date: Sat, 5 Jul 2008 13:13:33 -0700
To: <biggreen at lists.biggreen.org>
Subject: Big Green: "greener" concrete

Dear all, especially the structural engineers among us:
Are the following specs for concrete for a small plaza area "green"
enough?  (foot-traffic only, location Eugene, OR, i.e., occassional
ground frost):
-100% crushed/recycled concrete as sub base;
-80% crushed/recycled concrete as aggregate;
-50% of the cementitous material to be class C flyash.

Can these percentages (for this type of application) be increased? By
how much?

Thanks a bunch,
Peter


-- 
SOLARC Architecture/Engineering, Inc.
223 W. 12th Ave.
Eugene, OR, 97401

Ph: 541.349.0966
Fx: 541.343.1533


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