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RE: Concrete exposed to seawater

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I did find that the AASHTO Bridge Specifications do include specific requirements for "direct exposure to salt water" (4-in) and for "coastal" exposures (3-in).  (Could be reduced 0.5-in for low w/cm ratio.)  But let me be more specific regarding my questions:
If a performance specification for a non-bridge, coastal structure for a design-build project states that the design shall be in accordance with ACI codes and standards and with the recommendations of ACI 201.2R and ACI 222R, what are the minimum requirements for concrete cover for seawater and salt air exposure?  I did find that ACI 201.2R, Section 4.4.3, recommends a minimum of 3-inches of cover for "severe marine exposure"; but Section 2.4.3 references ACI 357R (for offshore concrete structures), which recommends 2.5-in for splash zones.  There is less discussion of exposure to "salt laden air" for structures near the coast in ACI 201.2R and ACI 222R, but ACI 357R does recommend 2-in cover for the "atmospheric zone not subject to salt spray".  I am a bit surprised that there is not more explicit direction in ACI and PCA documents on this subject, as such structures are not uncommon.
Bill Sherman

From: bart(--nospam--at) [mailto:bart(--nospam--at)]
Sent: Saturday, March 01, 2008 2:43 PM
To: seaint(--nospam--at)
Subject: Re: Concrete exposed to seawater

You can also go to, and the standard specs for DOT's  for CA, FL, OR or WA which I believe are available online....also make sure you use a well graded aggregate mix as you want as much of an even distribution of cement paste that you can achieve, without a lot of cracking.....

----- Original Message -----
From: William.Sherman(--nospam--at)
To: seaint(--nospam--at)
Subject: Concrete exposed to seawater
Date: Fri, 29 Feb 2008 16:17:06 -0700

Do any ACI codes or standards specifically address concrete cover requirements for concrete:
a. Directly exposed to seawater.
b. Exposed to salt laden air (coastal structures not in direct contact with seawater).
I am aware of some discussion in some ACI guides and commentaries and some requirements in European standards, but I am looking for "mandatory language" documents in the U.S.
William Sherman - CH2M HILL / Denver
Principal Structural Technologist
Structural Global Technology Leader - Water Business Group 

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