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Fwd: Re: Concrete in Salt Water Environment[Subject Prev][Subject Next][Thread Prev][Thread Next]
- To: wai(--nospam--at)euken.com
- Subject: Fwd: Re: Concrete in Salt Water Environment
- From: rlewis(--nospam--at)techteam.org (Richard Lewis)
- Date: 05 Aug 1997 18:01:21 GMT
Lynn It is absolutely astounding to me that on a glorious sunny California day, so many of us would be reading this newslist and responding so quickly, on Palm Sunday to boot!!! My 2 cents from experience at the Port of Oakland where we had about 20,000 piles built/maintained is you're on the right track with the (1) lower w/c 0.4-0.45. use o.4 if possible. (2) higher strength concrete 6000 psi or greater helps; The combination will help minimize the microcracks for water/chloride penetration (3) epoxy coated rebar as an additional layer of defense is still recommended, but only with vigorous inspection. You have to find the right inspector or R.E. willing to shove the contractor back on the inevitable nicks and dings on the coating. Otherwise, it is a waste of money (4) 2.5" cover is minimal. At the Port, we used 3" to provide more cover to protect the rebar. the additional depth also provides a greater degree of latitude for construction bloopers. (5) lastly, the sacrifacial anode is a good alternative / backup to a hard-wired cathode protection. Just have to remember to replace the metal every couple of years. My 2cents only. Ron Fong Fremont, Calif. In a message dated 97-03-23 09:51:44 EST, you write: << Dear List Members: We are involved in designing some structures that are for use in a research laboratory for marine environment (salt water). This is here in the US, and is in an area where freeze-thaw cycle is not an issue (Santa Barbara). I am in a quandary as to what to do with the reinforcing steel. We are going to use type V concrete, cover all steel with 2.5" minimum cover, use a strength of concrete in the range of 5000 to 7000 psi, and use a low W/C ratio (around .45) We are also going to be using a carefully selected source and gradation for our aggregate, to get a high density, low permeable, low reactive mix. We are considering using some of the admixtures that increase the density of the mix. From what I have read, the issue listed above are pretty much agreed upon by most professional in the design of concrete for a seawater environment. However, as I read studies and articles, there is a big disagreement on what should be done with the rebar. Epoxy coating, galvanizing, other treatments to rebar, and just using normal untreated steel seem to have their supporters and critics. It seems that plain old steel without any treatment may be the way to go, if you use a good high density mix with plenty of cover over the rebar. I am leaning in that direction, but the Owner (State of Calif.) seems to think that we should do something to the steel, and they do not feel comfortable without some kind of treatment to the steel. If someone who has had experience in this area could comment on what their views are, I would really appreciate it. I have read many studies and articles in Concrete publications (ACI, etc.), but there does not seem to be a consensus on this issue. Thanks Lynn >> --- Internet Message Header Follows --- Received: from server1.seaoc.org (bqe.com [126.96.36.199]) by host1.texramp.net (8.8.5/8.8.5) with SMTP id XAA05478 for <rlewis(--nospam--at)techteam.org>; Sun, 23 Mar 1997 23:59:32 -0600 (CST) Received: from emout08.mx.aol.com by server1.seaoc.org (NTList 3.02.10) id oa010596; Sun, 23 Mar 1997 21:53:18 -0800 Received: (from root@localhost) by emout08.mail.aol.com (8.7.6/8.7.3/AOL-2.0.0) id AAA27538 for seaoc(--nospam--at)seaoc.org; Mon, 24 Mar 1997 00:51:17 -0500 (EST) Date: Mon, 24 Mar 1997 00:51:17 -0500 (EST) From: Rlfong(--nospam--at)aol.com Message-ID: <970324005116_-1136059736(--nospam--at)emout08.mail.aol.com> To: seaoc(--nospam--at)seaoc.org Subject: Re: Concrete in Salt Water Environment Reply-To: seaoc(--nospam--at)seaoc.org Error-To: seaoc-ad(--nospam--at)seaoc.org X-Loop: seaoc(--nospam--at)seaoc.org X-Info: [SEAOC] Owner: seaoc-ad(--nospam--at)seaoc.org X-POP3-Rcpt: seaoc-ad(--nospam--at)seaoc.org X-Sender: seaoc-ad(--nospam--at)seaoc.org Precedence: list X-ListMember: rlewis(--nospam--at)techteam.org [seaoc(--nospam--at)seaoc.org] __________________________________________________ Richard Lewis, P.E. Missionary TECH Team rlewis(--nospam--at)techteam.org The service mission like-minded Christian organizations may turn to for technical assistance and know-how.
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