The irony in you suggestion is at the time asphalt was much cheaper but I dismissed the idea as it required regular maintenance LMAO So, I paid more and went with concrete smartly thinking the cost of asphalt maintenance would eventually equilibrate the additional cost of the concrete Uhh, that didn't quite work out LOL AND the "RED" color represents my backside LOLA
And I think I have tried just about every caulk out there but have lost track of which seemed better. None so far have stood out as being superior and if so only slightly. Sika flex was one of them

This does nothing to help with your problem, but it sounds like freeze/thaw issues with moisture getting in at the expansion joints ... I guess I understand the thinking of having an unbroken driving surface, no expansion joints to thump across ...
ever see the effect of a little dirt, a little water, and a winter freeze in a block of granite?

I think I would live with it, do what I could to slow the process, and move on.

Of course, firing all your employees HAS probably freed up a little cash outflow, so, ah hell, get it tore up and build a new one.

Sorry, just jabbing at you a little, I'm a sarcastic miserable old crank ...

Sorry this is so long.
Ideally the design would look at the total expansion and contraction from the hottest to oldest temperature rance and then take the length of the drive and make sure it is divided into adequate segments the harness the flex.
Having designed been involved with design of all sorts of roads, parking areas and airports areas with asphalt and concrete surfacing I've seen the god and bad.Not knowing the exact grade (steepness) of the drive there are at least two big forces working on the drive.Loading (dead load (weight of slab) and live load (weight of vehicles)) and thermal expansion. Concrete expands 0.0000055 per linear inch of concrete per degree F temperature change. This totals about 0.66 inch of movement per 100 feet with a 100° F temp swing from summer to winter. Thus 600' will try to move nearly 4".
If the pours were made in 33' lengths with transverse expansion joints it would still create problems. Each time the slabs expand and contract (especially on a slope) they will move down hill every year. If the original slab had no transverse e.j.'s it would be much like standing a wet noodle on end, it would move about as it chooses..
If the structural section is adequate, not just the gravel, but the underlying native material as well, I have a concept that you may talk with the contractor.
Think Bulldozer tracks. Segmented ribbon with cleats the dig into the earth.

Cut the 600' length drive into 5 100' lengths. Each cut will consist of two cuts 12" apart. Remove that concrete and trench to at least 18" below and if frost line is deeper, at least that depth.
Each trench needs to be at least as wide as the drive. Place 2 horizontal rebars and 8 or 10 vertical in the trench attach 1/4" styrofoam to the vertical faces of cut surfaces of the slab and fill with good structural concrete and finish the top. Once set scratch down the styrofoam and caulk with a top quality elastomeric caulk.

Beside the thermal and grvity, there is the resultant forces of tire rotation uphill and braking downhill that is pushing (creeping) the concrete down hill.

The above will not work is the navive soils are yielding (wet, clay or high organic. It needs a good road bed material of high "R" value.

Again not seeing or knowing the soil type I can only imagine.

For a quick test sift your native soils through a piece of window screen (fine screen) take that dust and mix in a bowl with some water until it's like putty. Put a 1/4 or half a teaspoon in your hand and roll it into a tube shape and when it gets 2 to 3" in length see if you can pick it up by one end or the middle.
https://engineeringtraining.tpub.com/14070/css/Roll-Or-Thread-Test-394.htm

I don't want to advise, nor cause you wasteful spending. The right guy on the grade will save you.
fwiw, if mine I'd look at the worse area and try something like I explained above. If it is widespread (entire length) it is definitely a design issue and up to you for approach to corral it in.

If you get frost that freezes in the ground it will cause movement. There are ways around it and most will require footings that are deeper than what the frost goes.

OK So we have someone who knows a bit about concrete etc.
The driveway has not moved at all or very little downhill. The center cut is opening side to side or left to right as you go up the drive way. But not in all areas. initially the gap appeared about midway up. It has spread a bit over the years both up and down the center joint. If one peels the caulk out the gap between the slabs are evenly spaced top to bottom, not angled or V'd. The concrete is otherwise perfect
Any further ideas and stabilizing it short of a complete tear out ?
Thanks

I'll agree with your first comment,

The second? They screwed me over quite well ( ~250K). The stabbing in the back was more costly emotionally that the financial lossleaving scars that will never heal. WHA WHA, my dumb a-- fault for believing and trusting. And if I had that 250K, I just might have it re done.

And no offense taken just wanting to clarify things. BTW one was my brothers son

I don't mind helping out with the hot weather, this is better than other options.
Failing mid length is a good indicator the basement is adequate, as is the base rock. This is where I'd expect to see exp cont creep.
How about trying two cross cut cleats first at 250' from the bottom, the second 50' further up the hill. if 30" deep it would be only a couple yards.
If you use the 8", or 12" wide trench and increase the styrofoam to 1" thickness, scratch it down 1" and apply sealant to form a 1" wide x 1" tall slug of sealant all the way across.
The material needs to be elastomeric and able the stretch and compress (much like a motor mount.
If per chance that "crack" is widening in the 50' section and the base was smoothly graded before the concrete was poured, one might be able to saw cut the 5' wide ribbon in half or thirds and with a big azz excavator (with street pads or lumber) to cross drive pull the slabs back together (before the cleats are poured. Of course any material in the crack needs to be mostly removed before "sliding" in together and reseal any cuts and e.j.'s similar to the above.
The thing with most (all?) elastomers is the depth should always be kept to the width of joint or the material will shear at the face of concrete(woor, glass, whatever material is being sealed). This is why backer or sand should always decrease depth of sealant.
p.s. sorry for any typos..... I noticed a bunch above..

Family can do the worst to people, far worse than an outsider. I learned early on just how bad it can be. Not sure why that is, you’d think family would have your back as the world is such an unforgiving place, but alas that isn’t the case. Our family business is long gone, untold amounts of money unaccounted for, inheritance swindled, and I’ve got quite a few that have no concept of what they did being wrong and therefore it’s been decades since I’ve spoken to them.

srt knows of what he speaks, I would listen to his advice.

How to build a road on either an uphill or downhill grade that might last 1000 years

https://www.zmescience.com/science/how-roman-roads-were-built/


scroll down to
“How Roman roads were made”

While your mind might first think
“Drainage, Drainage, Drainage”
now refocus on
Freeze/Thaw Expand/Contract
over thousands of cycles

You might object:
Romans had no idea about concrete !

No, no, no - their concrete was actually SUPERIOR to modern stuff
( made from unique volcanic ash )

I see potential for millions of expansion joints.

I do not anticipate ever speaking to any of the family involved nor those that took advantage of what we offered when help was needed. I do have a saying I use that applies, "Lessons paid for are best remembered" and I paid dearly.

To SRT, I appreciate your advice but it's likely out of budget.
To 360 View, thank you for your suggestions which I will look at but at this point the re-caulk with an 8 year warranty is appealing as I'm not getting any younger and can't even grasp what the driveway would cost to replace.
I do have another well know concrete company coming out to get their input. their specialty is stabilizing anything that is concrete and existing but moving.
To all thank you for taking the time to respond. I will update after the "stabilizers" look it over

It is a good idea to have experienced local contractors look it over.

A sign of a better than average contractor
is that he will want to dig some trenches or pits
along the side of “troubling” concrete slabs
to see what is below.

Using a “ditch witch” to dig a trench along one or both sides of the driveway
to both see the underlying foundation layers
and create long term drainage improvement
is not a bad way to start.

Ground control non-woven cloth
on the lining of edges of drainage trenches filled with sand/gravel
can work wonders.

I'd like to suggest that you approach the concept of the traverse cleats with the contractor.
Saw cuts and removal, reinf steel, concrete and sealant could be developed for each cut and do what you can. The excavator for trenching ann shift the slab sections.
I'm afraid that topically treating the underlying problems will do nothing except make it worse over time.
Keep us updated

Will do.
I will admit that paving is not anywhere on my list of experiences so your suggestion on the cleats is a bit perplexing and sounds $$$. I just went and took some pics which I will post. The one thing you mentioned is that the caulk needs to be as deep as it is wide if i understood you correctly. IF so some of the contracted caulkers have done a pretty poor job Some of what you will see was also done by untrained nephews for a few $$. The Pictures will start at the top and go down. the worst area is and always has been the middle area between the top and lower side "wing' driveway. Below that it is starting to move a bit but that's after 15 or so years. It willl look worse than it is due to the nephew job LOL. I cannot thank you enough for taking the time t o try and help one who knows NOTHING about this.

The last picture is of one of the piers put in up toward the middle where the problem started about a year after it was poured
Thanks again

3 more of the middle area which is the worst and the 4th is another one of the piers

Honestly I think the drive looks pretty good. Transverse e.j.'s would have prevented any side to side movement, imho.
This is going to be long again. Fixing these types of things is difficult to put into words, but fairly easy once the basic concepts are understood.
The piers will likely do little to resist over time. The forces moving the slab sideways will almost certainly push the pier over, or plow it through the soil. If a long deep curb had been put in place of the piers, ir would likely still move. It almost certainly is the expansion contraction.
I sketched up a little drawing in iso view. Think of the cleat as a transverse curb, or anchor pushing back against the slab forced as the concrete expands in the summer heat.
Your pics include on of the pier where a sealed crack in the drive slab adjacent. That is a good indication the slab is moving toward the pier. and the crack appears as that edge stretches outward.
In the upper left is a representation of the rebar layout.
If mine I'd put transverse bars at 6" apart stacked vertically and about 8' apart vertically.
In the lower right is a cross section of a slab with correctly placed sealant. The top is the sealant in a hot day in the summer, the bottom on a cold day in the winter.
Ideally the sealant hould be placed in the mid temperature range.
It appears the joint was routed before the sealant was placed? Just a guess. It's very good to rout (with a special router) any cracks to be sealed. 1, it removes old sealant, 2, it cleans dirt and other material from the surfaces, and it eats and drys the concrete. Alternative methods can work carefully scraping to the depth to be sealed, and using a wire brush on a gas powered lawn edger, etc.
If the wrong sealant is used it won't properly stretch and compress and can shear off the concrete (appears yours did this) and if too stable it won't compress at all and may continue "pushing" the slab outward as the temp cycles. It would the ultimate if you could find a contractor that can do "rubberized hot pour" These guys know how to properly prep and place and are in and out. Gheck with the local road maintenance dept, or airport, When they have a contract going the workers love pick up work for beer money. You may want to look up cold pour also.
If it were my driveway I'd first remove the de-laminating sealant and re seal with a quality product made for the purpose (of expansion and contraction). I'd then create a few new transverse expansion joints where you are seeing the most movement. Say, 3 cuts spaced 25' apart. A wheeled concrete "wet saw" can be used to cut across the slab and put e.j. sealant in there. depending on the width of cut (I'd shoot for 1/2") it will take a couple accurately cut passes, or, have a contractor rout any single blade width cuts. Contractor rental yards will have these various tools ar pretty reasonable rate, and contractors should have them already. The transverse cleats could be placed where the e'j locations are if it's found they are required later.
Keeping the cracks sealed as you are is a great plan. Water intrusion will wash out the fines of the base sand/gravel and freeze thaw will accelerate concrete deterioation. Keep water draining away from the sides of the drive by grading to slope away.
Don't fret about all this info as I really don't think the solution is going to be big budget.

The pictures help a lot.

Was the original driveway a steady grade when the concrete was poured,
and has the “dip” slowly appeared over time?

Just after the original concrete pour,
was the center high
and edges low?
( was there a “crown” )

I assume there is no wire mush in the concrete?

The T junction picture brings up the issue of
periodic winter rainfall causing water inundation of that lower sect,
particularly the far side of the lower section opposite the T.

Freeze/Thaw caused
contraction/expansion
would seem the root cause
made worse by saturated subsoil
that freezes unevenly
creating left or right transverse forces.

Cut more expansion joints,
clean out existing joints,
re-cauk.

The uphill side of the T-junction needs a drain that passes under (or through) the pavement of the side driveway.

A really tricky contractor
would lay a rubber bladder filled with water along side a shifted concrete section
anchor the bladder rigidly with stakes on one side
and let an overnight winter freeze
push the concrete slab back to its original alighment.

The pressures ice can create are one of Nature’s true wonders.

Sorry, I didn't attach sketch
p.s. It appears there is an e.j. where the loop drive intersects. Is the main drive in that location migrating away from the intersecting loop?
If it is you have the same situation there where the slab of the concrete of the loop section pushes the main drive in the summer. Again think e.j.'s with a good rubberized sealant.
I'd like to hear back with what you hear back from contractors.
I recall one GA airport project I worked on where the runway was over 4,200' long and 60' wide. It was "flexible" ac "Type A" (all crushed rock) pavement built on base and subase of FAA spec.
Longitudinal cracks appeared every 12' (width of the spreader box on paver x 5 = 60') and the edges of the runway were clearly not a straight line. Those long strips wiggled more than a snake on hot pavement. Transverse cracks were random and some were a couple inches wide.
Over the years several attempts at sealing the cracks failed and ribbons of sealant would pull out from the cracks.
To fix the plan consisted of routing all the transverse cracks 5/5" wide, foam backer pushed down 3/4 below top surface and hot rubberized material was poured in (and not squeegeed off).
Squeege would spread the material on top in a thin "bandaid" that would pull up on landing and takeoff. Well, the cracks reappeared and only when a runway light project was constructed (trench across runway every couple hundted feet for conduit)did the problem become obvious. Overnight we noticed the trench crumbling and the asphalt pulled back, through the day (115* summer temps) the cut edge of the ac would grow and move over the trench.
Once we figured it out when the trenches were filled and compacted, ac was placed and compacted and a saw and router opened up the edges (1/4" groove) backer and rubberized material.
No more cracks.