Concern: Recent cement pour - garage apron & sidewalk


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Old 11-29-07, 11:46 AM
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Unhappy Concern: Recent cement pour - garage apron & sidewalk

Hi,
Very concerned about a garage apron and sidewalk poured on Nov 17,2007. I am in MN the Contractor has 10yrs exp. Temps had been in 40s prior days to the pour. That day hi at 37 and low at 33. The concrete was covered with plastic same day. Ground was "warm", accelerant in concrete mix. Following 9 days had highs in upper 20's and 30's with lows in mid 20's or mid teens. Tenth nite had low of one below and lower single digits since.
I'm worried that it got too cold for cement to "cure" enough to avoid problems. It is still covered and nothing but foot traffic on it so far. Contractor seemed to think it would be OK. He has now added "blankets" but wonder if it is too late for that and if I should just remove and let predicted snows provide cover till trying to drive on it in about 2 weeks.
Pretty worried... anyone have thoughts about this?
 
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Old 11-29-07, 12:37 PM
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You should be fine. The concrete will continue to cure as time passes. Just don't use any de-icing salts or chemicals on it this winter.

Pecos
 
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Old 11-29-07, 01:33 PM
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Originally Posted by Dishguy
Hi,
Very concerned about a garage apron and sidewalk poured on Nov 17,2007. I am in MN the Contractor has 10yrs exp. Temps had been in 40s prior days to the pour. That day hi at 37 and low at 33. The concrete was covered with plastic same day. Ground was "warm", accelerant in concrete mix. Following 9 days had highs in upper 20's and 30's with lows in mid 20's or mid teens. Tenth nite had low of one below and lower single digits since.
I'm worried that it got too cold for cement to "cure" enough to avoid problems. It is still covered and nothing but foot traffic on it so far. Contractor seemed to think it would be OK. He has now added "blankets" but wonder if it is too late for that and if I should just remove and let predicted snows provide cover till trying to drive on it in about 2 weeks.
Pretty worried... anyone have thoughts about this?
=======================

Ok,perhaps the weather was a little less than ideal after your concrete was placed and finished but the world does not stop spinning this late in the year. You needed a driveway in Minnesota and it was November. If you would have postponed at this late date it's likely conditions would have deteriorated even more.

I think you beat Mother Nature and her attempts to foil your intentions out of a driveway. I agree with others thinking here and would say it going to be fine. And I doubt at this time (10+ days post pour) it serves any purpose to cover the flatwork especially considering you used an accelerant and temps were not as bad as they could have been the first night. Concrete does generate a small amount of heat as it cures. Certainly not worth the effort of removing this concrete.........at least that's the way I see it.

bs5
 
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Old 11-29-07, 02:19 PM
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Thanks... follow up question

Thanks Pecos and Bullshooter for the encouraging replies.
Since 5" or more snow is predicted Saturday (2 days out), it will be a big mess with all these big cement blankets, boards for weights, etc laying in front of my garage. Our cars are parked on the lawn, my garden tractor with snowblower and chains is in the garage set to go. If this snow comes I will have a deep mess of snow on everything and one can't shovel or snow-blow on top of the blankets without tearing them up.
Sooooo wondering if at this stage I should just pick up the stuff and roll up the blankets and wait for the snow. Then wait another couple of weeks to drive on it and start putting the cars (2) inside. (Was also advised not to drive on it for 28days.) Again.. if the snow is deep and should stay cold with further snows, this could possibly be the state of conditions all winter and nothing gained and no access to the garage or tractor with the snowblower on it?!
Any thoughts on this part of the predicament?
Thanks again!
 
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Old 11-29-07, 02:52 PM
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Concern: Recent cement pour - garage apron & sidewalk

Do you know what strength of concrete was used? Most of the good concrete suppliers in the area will refuse to sell anything less than 4000 psi air entrained concrete for that type of exposure.

What kind of "accerator" was used?

You apparently are north of the Twin Cities.

The blankets will continue to help as long as they are dry inside and you can put up with them. The snow is also a good insulator until it gets packed - I have seen unfrozen ground north of Duluth in February with a good snow cover.

Unless you you have a big person's "toy" a snowblower would be no problem.

Dick
 
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Old 11-29-07, 03:15 PM
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Cement concern.. followup

Thanks Dick,

Actually I'm straight west of Mpls on Hwy 7 not too far from SD border. I checked with the supplier and it is 4000psi and they use about a 1% non corrosiver chloride for accelerant.

RE the snowblower... I have just a Simplicity 19HP garden tractor with snowblower attachement and tire chains for traction. That would make total trash out of those blankets not to mention the blower would likely chew them up since they don't just lay nice and flat and then the boards on top of it ... just not a pretty picture.
I think since it has already been below zero with just the single layer of plastic for cover, any damage that may have been done is likely to have happened. No further cover will help out now but rather than nothing, the snowfall will do as well till it is "safe" enough (couple more weeks) to clean it off and drive the cars inside.

I tried to put a shovel into the ground the day after the below zero and it was pretty darn frozen... had the snow come first it would have been more likely to have done some good in this case.

Thanks a lot for your input and support!
 
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Old 11-30-07, 05:37 AM
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fergawdsake, don't trash,,,

those curing blankets,,, they're EXPENSIVE & reuseable.

these guys're right - not to worry,,, just get us'd to working in less than optimum conditions which rarely exist,,, either too hot, cold, windy, sunny, cold front moving in, rain,,, but that's the work so no sense complaining.
 
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Old 11-30-07, 06:35 AM
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Misunderstanding...

Seems to be the wrong impression coming across regarding this "cover" on the concrete.

I NEVER said anything about "trashing" the concrete blankets which I certainly know are costly and re-usable.

I was just explaining that if they are left on when 6 inches of snow is coming they could be there till spring... snow,ice and winds would do their damage over 4-5 months to them if left where they are.

The reason being that one cannot safely shovel or blow snow off of them without ruining them. So if they are left on and there is a heavy snowfall with no "thaws" for months plus additional snow throught the winter, there will be no way to get them (and all the additional weight boards) off until April?

It is not just a little incoveniece to park 3-4 cars half way to our road all winter with no way to get the snow removed and no easy way into the house. Sidewalk, front door access, garage door access, etc all buried under cement blankets topped with a foot of snow and then try to walk over all that several times a day? Can't keep a snowblower outside and expect it to be usable to clear the rest of the driveway all winter when it can be a foot or two of snow with blizzard conditions and 20 below zero at times.

Just trying to think it through as to what is most practical and makes common sense... I've put up with many "incoveniences" and weather extremes so not unaccustomed to dealing with messes etc... but why do it if not necessary and nothing gained is my point.

Thanks all
 
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Old 11-30-07, 02:35 PM
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Originally Posted by Dishguy
Seems to be the wrong impression coming across regarding this "cover" on the concrete.

I was just explaining that if they are left on when 6 inches of snow is coming they could be there till spring... snow,ice and winds would do their damage over 4-5 months to them if left where they are.

The reason being that one cannot safely shovel or blow snow off of them without ruining them. So if they are left on and there is a heavy snowfall with no "thaws" for months plus additional snow throught the winter, there will be no way to get them (and all the additional weight boards) off until April?

It is not just a little incoveniece to park 3-4 cars half way to our road all winter with no way to get the snow removed and no easy way into the house. Sidewalk, front door access, garage door access, etc all buried under cement blankets topped with a foot of snow and then try to walk over all that several times a day? Can't keep a snowblower outside and expect it to be usable to clear the rest of the driveway all winter when it can be a foot or two of snow with blizzard conditions and 20 below zero at times.

Thanks all
===========================

I believe as of Saturday (writing this Friday night) it will have been 15 days ago that you poured this. And you poured it with 1% chloride which speeds up the curing process. And you have observed certain disadvantages to leaving the blankets (which I concur with).

You know what, if that concrete job was done at my house in similar conditions I gotta say those blankets would be off that sidewalk/garage approach and my car and snowblower would be in the garage.....Gasp!

Yup, if it made you feel better a guy could stay back from and not drive near any corners for a while yet. And let's not leave the car parked on it dripping fresh salt brine and slop from the state hwy trucks as they clear those slippery snow covered trunklines in Minnesota. Some may disagree but the fact is you have done most everything you could do at this point. For all practical purposes, I gotta say you won't gain all that much by babying that darn old sidewalk. Some may disagree with me on this one but I gotta say any future damage the concrete endures was bred into it with or without you driving the family truckster over the top.

I'm in Northern Michigan and I believe you are going to get the same snow mix possible blizzard we're in store for on saturday. Let's take those blankets off, get that snowblower in out of the weather and slip the car over the top and into the stall. If you feel you must lay some 2 X 8's or whatever you have on the drive approach and drive over that han fine. I wouldn't even bother with that.

The 28 day standard your contractor referred to is a common bench mark used by engineers at which point concrete compressive strength tests can be taken and referred to. While it's true, the concrete gains strength up that 28 day ladder and keeps on gaining beyond that point. I can't see any benefit to punishing yourself any longer by staying off the concrete given all we have talked about here.

To each his own. Good luck

bs5
 
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Old 11-30-07, 03:18 PM
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Concern: Recent cement pour - garage apron & sidewalk

bs5 is right. -

My real concern was the lack of any mention of air entrained concrete, but I assume that anybody in your area should know you need air entrained concrete. For durability, you need to have the surface cured as well as possible.

With a good compacted base and 4000 psi you should not have any structural cracking problems. I hope he provided control joints for shrinkage - nothing can be done about that now.

bs5 - A little different climate than northern MI. Colder generally and much less snow (especialy if you are a UP'er). - Probably only 45" per year instaed of 100-200" and much less salt.
 
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Old 11-30-07, 05:25 PM
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Hi ConcreteMasonry,

If Phil was in the U.P.'s Keweenaw Peninsula (Northern most point in Michigan, a peninsula running from the upper Peninsula north into Lake Superior) he would have a blanket all right. But that blanket would consist of likely a foot of fresh and fluffy powder snow nightly. That could serve to insulate any ground or fresh concrete job.

http://www.alumni.mtu.edu/snowfall/

Luckily for me, I don't hail from the copper country and their record years of over 350" of annual snowfall. I'm from the Eastern end and as you say, we are in the120 -200" range or there about.

As you pointed out, I assumed that he got air entrained Portland cement in that he bought redi mix commercially. But I suppose you never know for sure unless one asks. In our area, we also specified limestone mix as opposed to a mix containing softer stone as it holds up better for out door pours that have to withstand freezing temps. The softer course aggregate stone concrete mixes seem to pop the stones over time as frost seems to permeate the softer stone. Soft stone mixes were fine for basement floors or footings however. In this area we are blessed with lots and lots of limestone but i know a lot of granite rock takes over in the Western part of Michigan's U.P.

bs5
 
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Old 11-30-07, 09:34 PM
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Thanks for all the help...

Hi again,

Thanks to all of you and especially to BS5 for your encouraging words... maybe it was missed but in message
#4, I mentioned that the redi-mix supplier was contacted and he told me they used 4000psi air-entrained concrete and a 1% non-corrosive chloride.

Yes the same storm system coming from the southwest will be passing across us and into the mid/upper northeastern US.
Still predicting several inches for us.

Soooo this afternoon with agreement from the contractor, we rolled up the several blankets, picked up all the lumber and put it in the empty garage stall till they can come and pick it up. They have been overwhelmed with trying to finish (rush) some last minute jobs. Now if the snow comes we will have insulation on the concrete for several more days and soon after I will clear it and begin driving the cars inside the garage. Yes they made the several relief cuts also.

The job looks pretty good with at least one annoyance.. the neighbor's dog tracked across it before it had set up so that irritation on an expensive project but still happy it is done.

Hopefully no scaling or chipping out next summer and all will be good.

Thanks again and I may be ending the thread at this point.
Merry Christmas ! :-)
 
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Old 12-01-07, 03:33 PM
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are you the guy,,,

w/the tractor-mtd snowblower somewhere as this scenario sounds familar.
 
 

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