Concrete driveway frost heave


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Old 02-24-07, 05:56 PM
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Concrete driveway frost heave

I'm getting some significant frost heave in my concrete driveway. There's a good half-inch discontinuity between two sections at the expansion joint. These are normally even with each other. This is the first winter of the four I've lived here that I've noticed this. I'm keeping my fingers crossed that the concrete doesn't crack. What are the chances that might happen? Why would this be happening now? Is there anything I can do to prevent it next winter?

The driveway is about 12 years old. The concrete is in otherwise pretty good shape. There's some very minor spalling. I've applied sealer hoping to prevent that from getting worse. I just don't want the thing to crack because of frost heave.

I live in northeast Wisconsin. Thanks for your replies......
 
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Old 02-25-07, 04:34 AM
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Concrete driveway frost heave

Your frost heave is due to the moisture conditions of the soil ubder the slab. Since this is a apparently a rare occurance, it must been the right combination of soil moisture and freezing cycles.

As you know, there is little do to a slab that is already in place. Any surface applications will have noe effect. The minor spalling may be due an accumulation deicers or a the long term (12 years) effect of freezing and thawing cycles.

Pay attention to your county load limit road posting that are made in the spring. Avoid running any heavy trucks on the driveway during that period (they probably could not get there legally anyway). This will allow the driveway to naturally settle back as much as possible.

Dick
 
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Old 02-27-07, 07:58 PM
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Thanks!! No heavy trucks at all on this driveway, that's for sure!! ;-)
 
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Old 02-28-07, 05:57 PM
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Concrete driveway frost heave

Not to much you can do but just let it settle down. In the future if you have to replace a section, dowel the sections together with rebar.Apply new expansion and drill through it into the concrete with a masonry bit a litter bigger than the rebar you will use. Slide rebar into hole and pour the new section tight around the othe side(9" on each side). This will either help keep it down or they will rise that little bit together.
 
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Old 02-28-07, 06:04 PM
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Thanks, but that goes way beyond my DIY skills, so can I ask you if that's a procedure that a driveway contractor would know about? (So I only have to tell him I'm getting frost heave and he knows what to do?)
 
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Old 02-28-07, 06:25 PM
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The only frost heave I am familiar with is puking from too many frosty mugs, but it sounds like you may need to seal the joints to keep moisture out of the subgrade.
 
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Old 02-28-07, 06:51 PM
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Concrete driveway frost heave

Sealing the driveway has little effect of the subgrade moisture. If ice lenses form under a slab, they create a barrier that collects moisture from below. This moisture freezes, thickening the lenses and force the slab upward. The area of heaving could be more than 4 or 5 feet deep in Wisconsin. The heaving usually comes from the deeper soil within the area frozen.

If you are in an area with a 4 frost depth for code for buildings, the actual frozen or frost depth away from a building can vary widely. With a heavy snow cover early in the season, it may only be inches or a foot for the entire season. If it is a bare and exposed area without snow cover, but with some traffic it can be 10'. In areas of very poor subgrades (peat), frost heaves can be several feet due to the pumping action of the traffic on the soil that raises and collects more deep moisture. In the spring, driving on these type of roads is almost like walking on a waterbed.

Dick
 
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Old 02-28-07, 07:04 PM
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Not sealing the driveway, just the joint, but I understand what you are saying.
 
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Old 03-01-07, 03:12 PM
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Dick - you must live in frost-heave country. LOL It's always amazing how rough the roads, and especially macadam roads get in late winter/early spring, and how they smooth out in the summer. ;-)

We had a period of very cold weather with only a very light snow cover, so I'm sure the frost went deep this winter.
 
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Old 03-01-07, 05:03 PM
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Concrete driveway frost heave

It's not always how deep the frost is, but the other conditions.

My cousins lived in Wisconsin and they all had a one week "mud vacation" every spring when many unpaved roads were impassible for the buses. The only other choice was a tractor and wagon.

Dick
 
 

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