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[SEAOC] Re:Concrete cracks[Subject Prev][Subject Next][Thread Prev][Thread Next]
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- Subject: [SEAOC] Re:Concrete cracks
- From: Oeyvind Saeter <oysater(--nospam--at)sn.no>
- Date: Mon, 23 Sep 1996 07:43:27 +0200 (MET DST)
>What I would like to know is, are ANY cracks in concrete serious? (A) If a crack is serious or not is depending on The "amount" cracks (length, width, depth and how often they appeare) The type/direction of cracks The enviroment (Cl-, CO2 ...) (B) The making of a crack is (simply said) either Shrinkage (it's natural for conrcete to loss volume in the hardening prosess) External forces or damages If you have a few vertical shrinkage-cracks in a basement wall (vertical and long cracks) - it would not affect the structure's capasity. If the crack goes all it to the rebars, and the envirolent is aggressve (like salt, Cl-) then the crack could leed aggressives to the rebar and then you got a corrosion problem. You can not say if one type crack is harmless and one other is not. Some types of cracks (like "crushing"-cracks due to overload) are more "risky" tahn others (shrinkage craks) - but the whole situation (See A above) determines if this is a harmess crack or not. The ONE thing one must have in mind is: If the structure has rebars and is exposed to aggressives (CO2, Cl- ...) you must seal off the crack to redusxe the risk of aggressives attacking the rebar. (This would normally apply to all outdoor structures in a cold/temperate climate.) PS! If the structure is exposed to frost and water, then cracks could reduse the freeze/taw resistance. Oyvind Saeter - oes ____________________________________________________________________________ Mr. Øyvind Sæter (Alternative: OEyvind Saeter) M. Sc. in Civil Engineering - Structural Analysis and Concrete Technology. Email: oysater(--nospam--at)sn.no | oes(--nospam--at)pvv.ntnu.no | oes(--nospam--at)pvv.unit.no All mail is forwarded to oysater(--nospam--at)sn.no WWW : http:\\www.pvv.ntnu.no\~oes Disclaimer: Information in this EMail has nothing to do with NTNU, PVV or my employer. ______________________________________________________________________________ ...
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