Q: Concrete didn't set, what did I do wrong?
Bill Zvonar
I poured a small amount of cement as a base for a lamp-post (there's
about a volleyball sized amount of cement). I mixed it a bit on the
thin side, and then it rained the next day and for the better part of
the following week.
That was about a month ago, and the concrete has never really seemed to
set properly. Now it's quite cold (below zero celcius), and the
I tried drilling into the concrete, but it's still not set... the drill
bit actually gets clogged with cement (it's got a clay-like
consistency).
So anyways, what did I do wrong? Does it sound like I poured the cement
too thin, or was it the rain/sogginess, or the impending cold weather or
a combination of the above?
Thanks, Bill.
--
Bill Zvonar, zvo...@nortel.ca (613) 765-4084, fax: (613) 763-7161
1285 Baseline Road, Ottawa, Ontario, Canada, K2C 0A7
Jay
Definitely too much water, which is the easiest way to weaken a new
concrete pour. If it hasn't set by now, it probably never will.
Jay A.
--
"May those who love us, love us; And those that don't love us,
May God turn their hearts; And if He doesn't turn their hearts,
May he turn their ankles So that we may know them
By their limping." - Anonymous
Michael Rothberg
Cold weather will retard the setting of concrete. The damp weather will
also retard the setting, but at the same time increase the strength.
It will set in due time.
Ray Cassidy
In article <l7q20dd...@bmerhc84.bnr.ca>, zvo...@bnr.ca says...
>
>I poured a small amount of cement as a base for a lamp-post (there's
>about a volleyball sized amount of cement). I mixed it a bit on the
>thin side, and then it rained the next day and for the better part of
>the following week.
>
>That was about a month ago, and the concrete has never really seemed to
>set properly. Now it's quite cold (below zero celcius), and the
>I tried drilling into the concrete, but it's still not set... the drill
>bit actually gets clogged with cement (it's got a clay-like
>consistency).
>
>So anyways, what did I do wrong? Does it sound like I poured the cement
>too thin, or was it the rain/sogginess, or the impending cold weather or
>a combination of the above?
>
>Thanks, Bill.
>--
>Bill Zvonar, zvo...@nortel.ca (613) 765-4084, fax: (613) 763-7161
>1285 Baseline Road, Ottawa, Ontario, Canada, K2C 0A7
You sure you didn't mix up mortar instead of concrete? Did the bag you used
contain what appeared to be cement, sand, and gravel?
Dan Hicks
In <l7q20dd...@bmerhc84.bnr.ca>, Bill Zvonar <zvo...@bnr.ca> writes:
>I poured a small amount of cement as a base for a lamp-post (there's
>about a volleyball sized amount of cement). I mixed it a bit on the
>thin side, and then it rained the next day and for the better part of
>the following week.
>
>That was about a month ago, and the concrete has never really seemed to
>set properly. Now it's quite cold (below zero celcius), and the
>I tried drilling into the concrete, but it's still not set... the drill
>bit actually gets clogged with cement (it's got a clay-like
>consistency).
>
>So anyways, what did I do wrong? Does it sound like I poured the cement
>too thin, or was it the rain/sogginess, or the impending cold weather or
>a combination of the above?
Probably the main problem was mixing the "cement" (I assume you mean
"concrete" or "gravel mix" -- if you just used pure "cement" then that's
your problem) "on the thin side". If you're not familiar with mixing
concrete, what you would figure is "about right" would be far too thin
to begin with. If you felt it was on the thin side it must have been
the consistency of soup.
Properly mixed, concrete doesn't really "pour". Rather it has more the
consistency of stiff mashed potatoes. If you mixed it too thin, and
then the rain got to it, you had a real setup for trouble.
The cold would only be a factor if the temp had dropped several degrees
below freezing in the first 48 hours or so after you poured the
concrete.
Luckily you only have a "volleyball sized" chunk to dig up and dispose
of. One wonders, though, why you felt you needed concrete for this lamp
post anyway. Unless the soil's really sandy or loamy it should be
possible anchor a lamp post in the soil without concrete, and often a
small chunk of concrete around a post will do more harm than good --
promoting rot/rust and encouraging frost heave.
Dan Hicks
Hey!! My advice is free. Take it for what it's worth.
http://www.millcomm.com/~danhicks/
Doug & Rose Miller
Michael Rothberg <mjrot...@laticrete.com> wrote:
+Cold weather will retard the setting of concrete. The damp weather will
+also retard the setting, but at the same time increase the strength.
+
+It will set in due time.
+
Don't be silly.
Look at the original post: "...That was about a month ago..."
If it hasn't set in a month, it isn't going to set.
+Jay wrote:
+> Definitely too much water, which is the easiest way to weaken a new
+> concrete pour. If it hasn't set by now, it probably never will.
+>
Not necessarily. Unless it was mixed so thin as to be better
described as "runny" it would still set properly, although it would
take longer. However, the rain the following day may have added
enough water to cause problems.
Another post suggested that perhaps Bill used mortar mix by mistake
instead of concrete; this seems unlikely to me, as mortar will set
quite hard also, when properly mixed.
Seems to me the most likely explanation is that the concrete mix
wasn't fresh. If you use an old bag of concrete that's absorbed
a fair amount of moisture from the air, you will get exactly the
clay-like consistency that Bill described, and it will never set hard.
Doug Miller
+>
+> Bill Zvonar wrote:
+> >
+> > I poured a small amount of cement as a base for a lamp-post (there's
+> > about a volleyball sized amount of cement). I mixed it a bit on the
+> > thin side, and then it rained the next day and for the better part of
+> > the following week.
+> >
+> > That was about a month ago, and the concrete has never really seemed to
+> > set properly. Now it's quite cold (below zero celcius), and the
+> > I tried drilling into the concrete, but it's still not set... the drill
+> > bit actually gets clogged with cement (it's got a clay-like
+> > consistency).
+> >
+> > So anyways, what did I do wrong? Does it sound like I poured the cement
+> > too thin, or was it the rain/sogginess, or the impending cold weather or
+> > a combination of the above?
+> >
+> > Thanks, Bill.
+> > --
+> > Bill Zvonar, zvo...@nortel.ca (613) 765-4084, fax: (613) 763-7161
+> > 1285 Baseline Road, Ottawa, Ontario, Canada, K2C 0A7
+>
Bill Zvonar
Thanks for all the replies.
Sorry for the loose terminology in referring to it as cement; the name
on the bag is "Concrete Stone Mix", and it's basically a mix of rocks,
sand and cement that you add water to.
In addition to all the things I mentioned, the bag of mix was sitting in
the garage all summer, so I had that working against me as well.
So, given the temp here nowadays (going down to -10C/10F this week, and
only getting colder), is there any point in me buying a fresh bag of
mix, and trying again, or is it too cold now?
As for anchoring the lamp post without the concrete mix, I'm drawing a
blank on how exactly I'd do that. The lamp post I have has a round base
with 3 holes in it that want to be bolted/drilled to something... what
is that thing (if not a chunk of concrete)? Maybe some kind of base
with a honkin' long spike that I can hammer into the ground?
Thanks again.
--
Bill Zvonar, zvo...@nortel.ca (613) 765-4084, fax: (613) 763-7161
Michael Rothberg
Bill,
Get an MT 3.5 gal pail. TAKE IT INSIDE YOUR HOUSE, Fill it with a
bagged concrete mix. Let cure inside your WARM house. Install the lag
bolts as needed. If your ground is not frozen, dig a hole to fit the
pail into. Bury the pail, install the post and viola’ your done.
Doug & Rose Miller
Bill Zvonar <zvo...@bnr.ca> wrote:
+Thanks for all the replies.
+
+Sorry for the loose terminology in referring to it as cement; the name
+on the bag is "Concrete Stone Mix", and it's basically a mix of rocks,
+sand and cement that you add water to.
That's the right stuff for the job.
+
+In addition to all the things I mentioned, the bag of mix was sitting in
+the garage all summer, so I had that working against me as well.
Yep, that's your problem right there. The cement (the fraction of concrete
that holds it all together) absorbed moisture from the air and hardened
in little nodules while still in the bag.
+
+So, given the temp here nowadays (going down to -10C/10F this week, and
+only getting colder), is there any point in me buying a fresh bag of
+mix, and trying again, or is it too cold now?
Well, you need a fresh bag anyway, but don't buy it until you're ready
to start work. Really, you should have a minimum of three days when
the temperature does not fall below 28F/-2C **after** the ground thaws
from your current subfreezing temperatures. A week of temperatures
above freezing is better.
+
+As for anchoring the lamp post without the concrete mix, I'm drawing a
+blank on how exactly I'd do that. The lamp post I have has a round base
+with 3 holes in it that want to be bolted/drilled to something... what
+is that thing (if not a chunk of concrete)? Maybe some kind of base
+with a honkin' long spike that I can hammer into the ground?
Well, I guess you could get a post-hole digger and make a hole about
four feet (1.2m) deep by about 15 inches (38cm) diameter and drop a
length of treated eight-by-eight in it. But since you can't do that until
the ground thaws anyway, you might as well use concrete.
Save yourself a lot of work and embed bolts, or sections of threaded
rod, in the concrete while it's still wet. Then attach the lamp base with
appropriate nuts after the concrete is thoroughly cured.
+
+Thanks again.
+--
+Bill Zvonar, zvo...@nortel.ca (613) 765-4084, fax: (613) 763-7161
+1285 Baseline Road, Ottawa, Ontario, Canada, K2C 0A7