metallic vs non-metallic grout 1

[whir]

What is the difference between metallic and non-metallic non-shrink grout. I have always seen non-metallic specified. Can anyone give examples of where you would prefer either?

 

[JAE]

Metallic grout is usually specified for machine bases where there is a high degree of vibration.

 

[Prepakt1]

Metallic grouts are also used in radiation shielding for reactor construction .This ia a very special grout and a very complicated proceedure .The grout is injected into a prepacked metallic aggrgate to form a concrete called prepakt concrete.

Intrusion Prepakt /marineconcrete.com

 

[youngstructural]

I didn't know there were useful metallic grouts available; From my experience in buildings and bridges non-metallic non-shrink is specified to try and prevent another 35 year Petrosky Effect from occuring...

Aluminum used to be used as an admix in concrete and grouts to counteract shrinkage, as it causes rise of hydrogen gas in the matrix and the pressure counteracts the shrinkage. Only the amount of gas created is very difficult to control, and concrete is of course porous... Over time the result can be severe deterioration.

Cheers,

YS

B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...

 

[KCRatnayake]

YS,
Would like to know further on Petrosky Effect. Can you send me some links on this?

Clefcon

 

[youngstructural]

Hey Clefcon,

Not easy to find, unfortunately. The british caught onto this in the late fifties, and the US seems to have been at the forefront of further research in the 1960s... But despite the fact that I often see references to academic articles, etc, you can almost never get your hands on them. I'll give you what references I have in my browser's favorites, as well as a run-down, and leave you to conduct your own search. Please post anything useful you find!

http://www.cement.org/tech/faq_aluminum.asp

http://www.seaintarchive.org/group/seaoc/mailarchive/2000a/msg01106.html

http://www.cement.org/bookstore/profile.asp?itemid=RX198

ftp://imgs.ebuild.com/woc/C650369.pdf

http://findarticles.com/p/articles/mi_m0NSX/is_5_47/ai_91139463

An old thread where this was discussed, and I posted a run-down on the reaction...

http://www.eng-tips.com/viewthread.cfm?qid=223306&page=9

(Review the SEAINT archive post for a PE's opinion on why you should be banning aluminum tools in contact with PCC)

There was extensive use of aluminum in in concrete for a long time, and by all accounts this can be quite successful. It can produce an effectively shrink-free concrete, but even though the specifics of the reaction are fairly well known, there are too many variables to reliably control the effect. Most engineers who know about it simply avoid it.

HOWVER, there are grout products that still use this reaction... Essentially in a grout you have fewer variables (no coarse aggregates to hide large quantities of undesirable elements, tightly controlled source of fine aggregates, factory mixing conditions, etc). I believe that many engineers who blindly specify "non-shrink, non-metallic" have no idea why, and probably routinely accept grouts with aluminum admixes.

Cheers,

YS

B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...