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  1. #1
    Forum Member stm4710's Avatar
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    Default Concrete spalling and rain?

    Would rain or melting snow etc. provide enough moisture inside a concrete foundation causeing it to have a better chance of spalling during a fire?
    Last edited by stm4710; 02-21-2004 at 01:26 AM.
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  2. #2
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    what is " spawling " ?

  3. #3
    Forum Member stm4710's Avatar
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    Sorry my mistake........its spalling.
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  4. #4
    Permanently Removed CALFFBOU's Avatar
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    Default Hmmm...

    I am NOT an expert on this, but this is my
    understanding. Spalding is when moisture
    inside hardened concrete is superheated
    and rises up "marking" or scarring" the
    surface of the concrete.

    So, with that in mind, I would guess-
    "No, rain or snow wouldnt have an
    effect.

    I could be wrong on this. I am just
    guessing with the knowledge I have.

  5. #5
    MembersZone Subscriber E229Lt's Avatar
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    Moisture that is locked in pocket can produce a small BLEVE and break the concrete. This can happen also when water gets inside and freezes.

    Air pockets can have the same effect but are not as common and usually occur on new pours not older structures.

  6. #6
    Forum Member PFire23's Avatar
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    Default

    Originally posted by firedawg803
    what is " spawling " ?
    Spawling: common misspawling of words is often seen here
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  7. #7
    MembersZone Subscriber mcaldwell's Avatar
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    Default

    Again this is pure conjecture, but concrete can absorb a considerable amount of water and will pull water significant distances if given the opportunity (this is largely why you put tar and plastic around a basement foundation).

    With that in mind, I think it is reasonable to conclude that in a wet environment, spontaneous spalling would increase when the concrete is exposed to fire. By how much, I couldn't tell you.

    There is an old joke about the CN tower in Toronto that calles it the worlds largest lawn sprinkler, because it drags water up hundreds of feet from the base before it is stopped by the first line of vapour barrier. You can often see it leaching out the sides of the concrete.
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  8. #8
    Forum Member stm4710's Avatar
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    The reason I ask is I went to a fire scene that happend last saturday and it was a 3 sided foundation with the 4 th side being the doors for a under house garage. If you were to look at the foundation (all that was left)straight at the garage side, on the left side it had no soil against it, it was just the concrete-no spalling. If you were to look to the right side the whole wall had spalled. This wall had dirt all the way to about 6" below the top,the soil was very very wet due melting snow. I noticed there were no sign of water proofing any where.

    I just wonderd if the soil mouisture could cause that spalling or would it have done it anyway.
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  9. #9
    IACOJ BOD FlyingKiwi's Avatar
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    Short answer is YES.

    Either the wall had no water proof membrane/paint between it and the dirt or it had failed.

    Then the concrete will take up moisture out of the dirt.
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  10. #10
    Senior Member FFMcDonald's Avatar
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    Not sure here-- but I'll give this a shot...

    My father has been in the concrete construction industry for about 30 years - so I have picked up a little bit.

    "Spalling" is when a piece of concrete big, small, or otherwise - gets knocked, chipped, damaged, falls from a concrete face. It usually occurs when concrete formwork is removed - and some of the concrete has adhered to the face of the formwork. It can also happen if/when construction workers/equipment hit the concrete with construction equipment.

    Concrete acts as a wonderful heat sink. Absorbs a tremendous amount of heat.

    If you are in a fire and direct the hose stream against the wall (a concrete wall) the rapid cooling of the concrete can cause a piece of it to fracture off.

    Improper application of a moisture barrier on a foundation can cause concrete to spall -- with or without a fire occuring.

    I hope this has shed a little light -- if not - ask some more questions and I'll see what I can do....
    Marc

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  11. #11
    GFDSlappyRob
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    Yes water and salt will cause the concrete to "Spall". Spalling is the rusting of the steel(rebar)re-enforcment that is put in when the concrete is poured.It will have a better chance of Spalling during a fire because when the water heats up it will contract back down to regular size too quickly allowing the concrete to separate from the steel. It is also more likely too happen when the concrete was poured when it is too hot and humid out.It is also known as "Concrete Cancer".I know this cause' I happen to work in concrete and excavation.
    Last edited by GFDSlappyRob; 02-22-2004 at 01:44 AM.

  12. #12
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    I have never heard of spalling, and I have worked in the construction industry for several years. As far as I have seen, there are two "for sure" things concerning concrete: #1 - It will turn gray, #2 - It will crack. It does not matter how good you or your material is, these things will remain constant, so for the whole spalling deal, you learn something new everyday.

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