I am hoping someone may input on a problem I've been dealing with for over 15 years.
I have a 600' long driveway, 10 ft wide that goes straight uphill a pretty steep grade. The driveway is 6 inches thick and fiberglass reinforced (BAD IDEA IMO now) but it was the contractors choice at the time. It was poured over a gravel base that was well-established for about 10-15 years).
About a year after it was poured it appeared the center joint (cut in) was opening up and the slabs were sliding sideways. The contractor came out, was puzzled saying he had only encountered this once before. He proceeded to drill 6" holes down the side he thought was moving (which is open to the entire front acreage). He then filled the holes with concrete. That seemed to slow things down but not stop it.
On the other side of the drive, is a 12 foot wide V shaped drainage are about 15-20ft wide for the runoff from above with a grove of trees another 20 or so feet wide. I even reshaped the drainage area as there was a slight high spot that I thought may be sending water under the drive during the spring thaw.

I then wondered if it was dropping on the outside edges due to the weight of delivery trucks, tow trucks etc. But the edges of the joint are not angled (V's) as one would expect if this were the case, but straight up and down

So, I am wondering if anyone has encountered a problem like this and or what might be done to stabilize it. It's not sliding down, but rather sideways. Originally, the problem was most prominent in the mid-way up the drive, but has slowly moved both directions (up and down) over time. The driveway otherwise is in perfect condition with not heaving, cracking etc.

It is an annual thing to re-caulk a substantial portion of the center joint and I have likely spent more $$ keeping it sealed than I did having it done (12-15K?).
Any experiences, thoughts, suggestions, comments appreciated

It sounds to me like it is the underlining soil moving or settling. is there evidence other than the slabs that the surrounding soil is/has moved?

Nothing noticeable. With a gravel driveway being there for over 10 years before, I have been told by many that should have been more than adequate and a well established base to pour on

Maybe not the most desirable option but could you make up some stainless flat bar straps and set 2 anchor bolts on each side of the center joint? You can get anchor bolts that use screws instead of nuts that are relatively flat. They would run the length of the driveway and be located in the center.

How deep were the 6" holes that the contractor drilled and filled with concrete? I'm thinking to drill much smaller holes, maybe 1 1/4" diameter, through the concrete at strategic places and pound in 3 or 4 foot long pieces of 1" diameter rebar down below the top surface of the concrete and then fill in the holes with concrete level with the top surface so the repair isn't visible. Hard to believe that wouldn't stabilize it. It would be relatively inexpensive and something you easily could do yourself.

If I'm reading this right, the driveway is splitting longitudinally at the center saw cut joint? Driveway is only 10' wide? And getting wider? Or is it an expansion joint? How wide is the gap now? Expansion joints normally are cut across the narrow portion, not the longitudinal direction. Hindsight being what it is, post tension (VERY unusual if not never for a driveway) is how it should have been done. Retrofitting a half way post tension system would be terribly expensive and may not be successful anyway. Or terribly expensive squared, LOL

Some good info at the link below.

https://www.concreteconstruction.ne...etrofit-using-external-post-tensioning_o

I'm sorry, I really don't have an answer. But rebar would have been better, might not have prevented it though.

I have a similar situation, an approximate 30' long double driveway on a 15% slope. The driveway was poured about 40 years ago and over the next 10 years it slid toward the street such that the first expansion joint opened from about 3/8" to about 2". The only thing that seems to be stopping it from sliding further is the paved street. But if you look closely, the street adjacent to the curb is deforming. So far I've done nothing other than fill the expansion joint gap. I'm not really sure what would stop it. My Father always maintained that the earth is always moving. If you look at leaning retaining walls and out of level A/C unit pads, I think my Father was right.

My first impression is the concrete is "monolithic" and floating on material that is not able to support it.
Without visiting the site is hard to diagnose. I feel it is a foundation problem, and that should be investigated first.
I'd check with Soil Conservation Service to determine if there is landslide activity on your site, or even adjacent.
Then, water intrusion under the slab should be investigated.
The "R" value of the native material should have been determined by the designer.
I'd hesitate spending any more $ on repairs until the above is determined.
Sometimes it is impossible to "stabilize" for a concrete surface and a "flexible" road bed would be appropriate.
Flex road-bed can be done in several ways and method determined after the first three above are determined.
My guess is if the entire drive is moving you have a deep seated sliding mass. If it's located in one or two areas it's water.
Loading and unloading the slab by driving on it pumps water in and out of the "structural section" and the "fines" in the gravel are pumped out thus destabalizing the road
Additionally forces of vehicles on the concrete can have the slab walking across the concrete/gravel contact plane, or more likely an undelaying slip plane of different soil types or native and fill constructed upon it..
Partial removal of the worse segments and de-watering (drain blanket with drain pipes) and install of a "geo-grid" may help.
Again too far away to tell, so get the soil engineer on site.

I wondered About doing something like that but am concerned it may cause stress cracking around the bolts and result in a bigger mess

The depth of the holes is something I don't know But if memory is correct I'd say3.5 -4 ft.
And you r suggestion or something along those lines was another thought I had but not sure about how far to go down, the cost, finishing, possible long term issues (cracking etc.) I'm still working 7 days a week trying to get caught up on commitments I made to customers over a year ago. So my doing it is not possibly at this time BTW,
NEVER TREAT AN EMPLOYEE AS ANYTHING MORE THAN A TOOL

Have an engineer come out and assess what you have going on.
In my mind you're going to have to construct a concrete retention wall to prevent it from sliding further.

1st question, Yes
2nd question, yes
3rd question, in areas an inch or so others hasn't moved at all ( keep in mind it's 600+ ft long)

Hindsight? I would've used a different contractor or at least required wire fence or rebar
I keep thinking of a LARGE HYDRAULIC C CLAMP , or maybe 12ft long 1" diameter all thread
LOL
And the tensioning idea is great but a bit too late

thanks for the response, but likely a bit too expensive for my retirement based budget. I have had several different civil/ construction engineers look at as friends / customers and they have all shook their heads

it's pretty much level ground but uphill. the slabs are slipping sideways on the level plane.

I just had a concrete/ caulk guy here than say water is getting under it form seepage at the joints that are all caulked but some are likely seeping. h quote 5K to re-caulk the entire driveway with an 8 year warranty on the caulk not separating from the concrete.
Hmm I'll be getting up there by that time. Might also try to see if i can get ahold of the original contractor to see if he can offer anything. Strange problem

I do want to thank all that have responded so far

I must say, I don't understand the original thought of splitting a 10' wide driveway side to side. That doesn't even make any sense to me. My driveway is 19' 6" wide and it isn't split side to side at all.

My old drive was 16' wide and was split side to side, and it was spreading apart, I think each side was allowed to lift and drop separately as the weight of vehicle traffic crossed the two pieces, and as the cement rocked against each other they pushed themselves apart. Your driveway only being one vehicle width wide, I think the problem would be compounded. Since the entire driveway isn't spreading consistently, I suspect there may be water issues under the drive at the points it is spreading more.

Unfortunately, I don't see a permanent solution, short of replacing the areas that are spreading. I wouldn't even consider that with only an inch of spread, fill the gap. Its been there 16 years and has only moved apart an inch, if it continues at that pace, in another 16 years it may be a 2" gap, but you have had things done to slow the change, it may not move any more.

Truthfully, I'm pretty impressed that a 16 year old 600' driveway isn't cracked! My 15 year old 88' driveway has a couple of very small cracks in it. Gene

Not being a wise guy, sometimes one has to cut to losses. The lateral movement is not the problem but a product of under laying materials.
I agree with the above that wheel loading together with basement soil, base rock (hopefully not sand), and/or water intrusion is the problem.
The concrete is most likely starting a long slow process of moving about and failing.
I have only seen the solution to be to pulverize and use the existing as crusher fodder to build up the structural section upon which to construct a correctly designed drive.
If the under laying soil is clay or high in organics or located on the vicinity of a spring you will need to de-water with french or under drains.
I offer this not to distress, but as an honest opinion.

The base was gravel that had been in place for about 15 years with no real problems in spite of the grade, everyone i have spoken with has said that should have been an ideal base
Right now I'm leaning towards the guy that was out today. has 31 years exp and believes it just water getting under it from all the joints etc. Even though they are all caulked he pointed out several are no longer sealed.
He wants to re-caulk the entire thing with an 8 year non pro rated warranty. ~ 4.5K works out to about 45.00 a month which is a lot less than I have been paying on an annual / semi annual basis. he works for the owner and has been in business for 10 years. have to do a bit more research but the warranty is appealing in spite of the cost
Thanks again to t hose that are responding

I doubt you will get enough of those to withstand the weight of two sections pulling apart like you describe. My thought is it will either bust or start big cracks on your otherwise smooth concrete surface.

I agree that something is moving under the surface. Seems odd that in this time you’ve not had a really bad movement though. Maybe you can ride this pony 15 more years? That would reach the lifespan of a concrete driveway. It lasting over 30 in good shape is a bonus.

I don’t think I’ve seen a ten wide drive with an expansion joint on the width. Usually only see expansion used when you have two different pours. The control joints need to be about 8 feet apart or the concrete will create those for you for free. Look at pours by boobs and you’ll see a big crack spaced about that far apart on them.

I’d call up a local concrete supply house and see what Sikka flex costs per tube and try to figure up the coverage area you need. Maybe push a backer rod down in there to lessen what you have to put on it. You could do a test area and see what you think. Should be way less than 4-5k. I mean way way less. You could probably get a handyman to do it if you aren’t able to bend down that much if you go buy the materials. It’s really just like caulking work.

Or have an asphalt guy do the lower portion and then try for a repair of just what’s up near the house. Asphalt is usually like 25-30% of the cost of concrete. I detest it near a house or for a short driveway, but could be convinced to live with a few hundred feet away from the house.