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 $$ keeping it sealed than I did having it done (12-15K?). Any experiences, thoughts, suggestions, comments appreciated
It sounds to me like it is the underlining soil moving or settling. is there evidence other than the slabs that the surrounding soil is/has moved?
Nothing noticeable. With a gravel driveway being there for over 10 years before, I have been told by many that should have been more than adequate and a well established base to pour on
Maybe not the most desirable option but could you make up some stainless flat bar straps and set 2 anchor bolts on each side of the center joint? You can get anchor bolts that use screws instead of nuts that are relatively flat. They would run the length of the driveway and be located in the center.
Last edited by CYACOP; 06/21/2206:49 AM.
Re: Concrete Driveway problem / question
[Re: CYACOP]
#3052126 06/21/2208:04 AM06/21/2208:04 AM
How deep were the 6" holes that the contractor drilled and filled with concrete? I'm thinking to drill much smaller holes, maybe 1 1/4" diameter, through the concrete at strategic places and pound in 3 or 4 foot long pieces of 1" diameter rebar down below the top surface of the concrete and then fill in the holes with concrete level with the top surface so the repair isn't visible. Hard to believe that wouldn't stabilize it. It would be relatively inexpensive and something you easily could do yourself.
Re: Concrete Driveway problem / question
[Re: TJP]
#3052130 06/21/2208:31 AM06/21/2208:31 AM
It is an annual thing to re-caulk a substantial portion of the center joint and I have likely spent more $$ keeping it sealed than I did having it done (12-15K?). Any experiences, thoughts, suggestions, comments appreciated
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
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.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
Re: Concrete Driveway problem / question
[Re: TJP]
#3052158 06/21/2211:00 AM06/21/2211:00 AM
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.
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.
I wondered About doing something like that but am concerned it may cause stress cracking around the bolts and result in a bigger mess
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.
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.
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.
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
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.
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
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.
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 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
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.
I wondered About doing something like that but am concerned it may cause stress cracking around the bolts and result in a bigger mess
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 want my fair share
Re: Concrete Driveway problem / question
[Re: SomeCarGuy]
#3052301 06/22/2212:19 AM06/22/2212:19 AM
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.
I want my fair share
Re: Concrete Driveway problem / question
[Re: SomeCarGuy]
#3052351 06/22/2210:30 AM06/22/2210:30 AM
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.
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.
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.
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 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 ...
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..
Re: Concrete Driveway problem / question
[Re: TJP]
#3052587 06/23/2212:16 AM06/23/2212:16 AM
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 ...
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
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.
I want my fair share
Re: Concrete Driveway problem / question
[Re: srt]
#3052589 06/23/2212:27 AM06/23/2212:27 AM
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.
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.
Re: Concrete Driveway problem / question
[Re: TJP]
#3052934 06/24/2211:20 AM06/24/2211:20 AM
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.
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.
Re: Concrete Driveway problem / question
[Re: TJP]
#3053204 06/25/2207:16 AM06/25/2207:16 AM
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.
Re: Concrete Driveway problem / question
[Re: srt]
#3053252 06/25/2211:47 AM06/25/2211:47 AM
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.
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.
thank you again for taking the time for this. I had never thought about expansion in the heat and contraction in the cold. But will say I have noted the stretch and squeezing of the sealant at various times but never gave much thought to it. The cleaning is also something that none of them have done to my knowledge but does make perfect sense.
I believe I am getting a grasp of your recommendations which is to cut more 1/2" joints across the drive where the movement is most noticeable and reseal. This I'm guessing will reduce both the expansion & contraction as the slabs are now smaller, Correct? The two I don't grasp is "The transverse cleats could be placed where the e'j locations are
Was the original driveway a steady grade when the concrete was poured, and has the “dip” slowly appeared over time? the dip has always been there
Just after the original concrete pour, was the center high and edges low? ( was there a “crown” ) A light crown so the water would got to the edges
I assume there is no wire mush in the concrete? CORRECT, bad allowance on my part, as he asked if i wanted wire fence, reboar or fiberglass reinforced. I left the choice up to him as I figured he SHOULD know best
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. The area atthe junction and below ahs bee pretty stable The section that extends to the building does have some drainage issues that do need to be addressed mainly near the front of the building.
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. that area is actually sloped up and towards the front of the bldg. See the preceding comment
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 alignment.
The pressures ice can create are one of Nature’s true wonders.
Both of you have been awesome for educating me a bit and I know have a bit more knowledge to put the screws to the contractors if needed. As mentioned in the response to SRT I now know the previous contractor's did not prep or fill the joints properly to allow the proper amount of sealant. Wonder why it's failing having spent 20+ years of my life in engineering I get frustrated sometimes when I don't understand why something is happening or worse yet why or how it works. I'm not an authority at this pint but have a lot more knowledge than I did several days ago Thank you both again and I will keep you posted
I believe I am getting a grasp of your recommendations which is to cut more 1/2" joints across the drive where the movement is most noticeable and reseal. This I'm guessing will reduce both the expansion & contraction as the slabs are now smaller, Correct? The two I don't grasp is "The transverse cleats could be placed where the e'j locations are
Yes, more transverse joints with sealant. Regarding the cleats, that would be the transverse "curbs" if you will. Do the transverse cuts and seal first (make sure cuts go completely through the slab and all loose material removed - compressed air works good), install foam and seal it up. If months or years later you see the slab continue to walk the transverse cleats (reinforced concrete concrete curbs) can be installed using the previously cut exp joint as one side of the 8" to 12" wide trench. Further up described as at least as wide as the drive, and 24" to 30" deep. The upper left grid like sketch is looking at the face of the cleat. All it's purpose is to keep the slab from continuing a down hill walk. Think of expansion and contraction of the drive slab as a caterpillar going down-hill. Each summer it attempts to hump up, and in the winter it pulls it self down hill.The cleat is just there to keep it pushing against 20, or 25 square feet of dirt resisting it. It's easy to push over a fence post sunk 4" or 6" yet if that post is 24,'" or 30" deep it will be very difficult. Think of it as a bulldozer skimming off the top soil, vs making a big deep cut. I can imagine if the cleats were installed one would notice the e.j. on the up hill side be narrower, and downhill wider after a few seasonal cycles. Additionally, this is getting into the real nuts and bolts. Every time a car goes up hill the tires push the slab downhill, and conversely going down hill braking has the same effect. A famous physicist once said for every action there is .....
In our youth “cleats” might have been the round “grabbers” on the soles of football or soccer shoes.
the meaning of “cleat” here is like the downward crossways bars on bulldozer tracks
these cleats “grab down into soil” and resist slippage of both bulldozer tracks and in the future your “driveway” which is just a wide concrete “trackway” that never is supposed to slip or move.
e’j or e.j. is short for “expansion joint” - the narrow slots running left to right in the driveway made either by the original wood forms for concrete sections, or sawed cuts that are filled with caulking over foam, which exclude unwanted ice, or block toothpaste like mud flows from underneath.
Thank you good sir! I could not come up with a better word for "grousers" that might be mistaken for a growler. This from wiki:
Grousers function by trapping soil against the contact area of the track (in this case the slab). It is the shearing of the soil against itself that generates tractive force. The gross tractive effort, or soil thrust, of a vehicle (or sliding slab) may be calculated.
There are some alternatives that could be incorporated for ultimate stability in this driveway situation. I believe the slab was not reinforced, thus I did not include doweling the slab into the wall with sliding sleeves, nor cutting the slab at a slight angle so that when it expands it is not forced up and over the cleat,, rather it is forced downward (and the soil would resist the slab from sinking) much like a dovetail.
Re-thinking the design (before construction). 1 - soil analysis 2 - design drive with some amount of "slight curves" and expansion joints at beginning and end of each curve, or 3 - design straight drive where it is divided into several 50' segments. Each segment would be a flat slab, with a "cleat, grabber or grouser" at the upper end of each slab. Each upper slab could be doweled with sliding sleeves at each edge. The Cleats would need to have reinforcing steel bent like "L" shape the long segment going into the slab and the short down into the "cleat". the upper slab would include expansion joint material between that slab and cleat below.
Lastly think of a bridge abutment, or even a joist hangar and how it incorporates short curbs to keep the bridge deck in alignment or joist properly located. The op drive is unconstrained and is pretty much floating around being pushed by thermal and loads. The wearing surface looks great; it's not breaking up, so feel the materials used are adequate. This is an interesting situation and I hope to hear updates.
Do the proper expansion joints and I think that drive will out last us all. Cleat-less.
Re: Concrete Driveway problem / question
[Re: 360view]
#3053411 06/26/2206:53 AM06/26/2206:53 AM
The least amount of concrete would have been poured if the driveway slabs were flat bottomed and a consistent thickness. We must assume this as “the worse case” since the contractor would make a higher profit.
But a knowledgeable professional would have made both lengthwise and transverse “ditches” in the subsoil before the concrete was poured to create concrete “cleats” meant to help the slab resist sideways and downhill drift. Since most cracks occur near edges it is good practice to make the concrete thicker at edges, and especially at corners. On automobile driveways it is good practice to make the concrete thicker underneath where the tires will roll.
Combine these two “practical tips” and the unseen bottom of the concrete will not be “pool table flat” but rather “lock and key” hugging the subsoil.
Ultrasonic thickness testers could be used to see if this varying concrete thickness exists. Ultrasonic testers are way cheaper today than they were in the 1980s. A cheap IR Temperature gun could also be aimed at the driveway on either a very hot or cold day. On a hot day the thicker concrete might read a bit cooler than nearby thinner. After a cool night it might read warmer.
If Superman is flying overhead just put a Lois Lane look-a-like in a skimpy dress to wave him down for a quick X-Ray vision.
Re: Concrete Driveway problem / question
[Re: 360view]
#3053455 06/26/2211:13 AM06/26/2211:13 AM
The least amount of concrete would have been poured if the driveway slabs were flat bottomed and a consistent thickness. We must assume this as “the worse case” since the contractor would make a higher profit.
But a knowledgeable professional would have made both lengthwise and transverse “ditches” in the subsoil before the concrete was poured to create concrete “cleats” meant to help the slab resist sideways and downhill drift. Since most cracks occur near edges it is good practice to make the concrete thicker at edges, and especially at corners. On automobile driveways it is good practice to make the concrete thicker underneath where the tires will roll.
Combine these two “practical tips” and the unseen bottom of the concrete will not be “pool table flat” but rather “lock and key” hugging the subsoil.
Ultrasonic thickness testers could be used to see if this varying concrete thickness exists. Ultrasonic testers are way cheaper today than they were in the 1980s. A cheap IR Temperature gun could also be aimed at the driveway on either a very hot or cold day. On a hot day the thicker concrete might read a bit cooler than nearby thinner. After a cool night it might read warmer.
If Superman is flying overhead just put a Lois Lane look-a-like in a skimpy dress to wave him down for a quick X-Ray vision.
Any sub slab work is really going to be too costly and not knowing how thick is not paramount to know, only because the slab looks pretty good and not breaking into small pieces. I thought about different means to core through the slab and pin it to sub soils, etc, but again not knowing the soil types it could be a big waste of $. Easiest is to drill with a small diameter masonry bit until it breaks through and measure depth with a small dowel. Seal with caulk.
I'm with you on the table flat sand or compacted rock bedding. Flat will not provide enough shear to keep the ice (slab) from sliding off the table. the transverse cleats are likely the most economical at this point for o.p.
Brain storming, in case anyone plans construction. 1 - A series of 4" diameter holes could be drilled 24 to 30" deep and filled with concrete and a single #4 or 5 bar that is bent over and tied into the slab reinforcement. One would be effectively building a pier rather than floating docks. 2 - Condtruct 6" wide x 16" deep concrete curbs each side the length of drive with steel at least top and bottom with a few verticals and also e.j.'s every 50 feet or so. The top of curb would be flush with the top of drive slab unless water was to be ducted. After set, a 1/4" foam type e.j. on the face of each curb and pour the slab in 50' segments with e.j. staggered to align mid point between the curb e.l.'s.
Re: Concrete Driveway problem / question
[Re: srt]
#3053465 06/26/2211:44 AM06/26/2211:44 AM
Where Tim is is the loess hills formation, basically blown in silica, mica, silt, and vegetation, right next to a major river and floodplain where the heaviest formations would be. Add in the fact it is on a severe grade I can't believe it stayed as nice as it has. Looking at the pics I say the fiberglass did its job...very few cracks other than the control joints. Concrete around here with mesh always seems to crack and show the mesh lines, the control joint down the middle might be a good thing, mine was poured in 1980, 12ft wide 144 ft long, with mesh, and it cracked right down the middle just like the contractor said it would after the first 20 below weather we had. So cut or not you would have a crack there, just my opinion but I think your contractor did a good job given the soil there, maybe some rebar would have helped, but I bet you would have even more cracks. When they built the interstate near you in the 70s they dug down to light brown dirt and pulled a the dark soil out and filled it in. Remember how the hills were dug out around you years ago, a lot of that was from the interstate construction to get better soil. If that $4500 bid includes digging the old caulk out, grinding the edges, new caulk, and a warranty jump on it. We both know no way it all lasts 8 years.
A big thanks to All as I have much more knowledge than I did several days ago. I'm going to see what the second "problem solver" comes up with and what their bid is. To clarify, it was poured 6 inches thick and that was15 or so years ago. The driveway to my observations has not moved a bit up or down hill. Only the center cut has opened mainly mid way up between the "wing' and top. The top section hasn't moved at all or very little either directon. The lower section below the "wing" has just recently moved a small amount in the last few years (again the center cut only). You have all made me feel a bit better about the original contractor whom I've questioned in my mind all this time. He was selected as he was a friend of a neighbor that became like a surrogate father to me after moving back here. The neighbor who was in construction all his life, unfortunately passed away several years back. I later found out that the contractor that did the driveway mainline business was pouring foundations and walls for new homes That just might explain some of this Thanks again to all and i'll report back in ~ 5/6 days.
If the ground under that driveway is loess then it is AMAZING that you have had so little trouble.
Let’s hydraulic hammer it all to pieces take pictures and publish an article in Engineering Monthly magazine titled “Minimal Sift Pavement Design Survives a Decade”
If the ground under that driveway is loess then it is AMAZING that you have had so little trouble.
Let’s hydraulic hammer it all to pieces take pictures and publish an article in Engineering Monthly magazine titled “Minimal Sift Pavement Design Survives a Decade”
No problem as long as you replace it LOL and that's 1-1/2 decades
So loess ia a new one for me and I read a little on it. Do you know if any calcium was worked into the original soil and watered and graded before the sand or rock base was placed? At this point I'd NOT recommend the grousers. It'd be worth trying the e.j.'s in the worse area. It may be worth discussing with the contractor a combination of the expansion joints AND also reinforced concrete curb along the slab where it's moving. These types of problems are difficult to diagnosis without knowing all the site conditions. The reason the cleats won't work is the weight of a vehicle will simply "push it down" into the loess soil. Of course they could be designed and constructed wider and with re-worked and supplemented sub grade material (most likely wider).What I do not know about loess is if it liquefies when you drive over it. i.e. water squeezes out and carry's fines up through cracks and appears on the surface. or elsewhere. As you drive off the area the water rushes back in. Try the correct sealing and ea couple e.j.'s and see if it's livable. Two about 10' apart for a potential future project if it continues to displace outward. This future work would be to remove the concrete in that section and excavate downward between 18" and 24". working and treting the removed material with calcium and/or incorporating or replacing the excvated material with good rock subbase material and compact it well (90 to 90% compaction. Then grade the top with base rock pour a reinforced slab that includes four "keepers" that are about 12" wide and deep and also run under the edges of the cut surfaces of the existing slabs. The goal is to create a seat, or abutment with little wing walls. This new slab and keeper/abutment will need reinf. steel that is tied into the slab. These keepers should be poured at the same time as the slab and the entire "unit" of 2 keeper/abutments and the slab would be monolithic. This is something I would not let a contractor design and is should include soil analysis. You'd be effectively creating a floating foundation/road with curbs to contain movement of the up and downhill segments. The other concept is similar and consists of cutting 3' (more or lass determined by engineer) digging down 24 to 30" across the drive , rework the soil, pour a 3'wide reinforced footing and 12" with clete (stem wall, all reinforced with steel) and then back fill and compact therest of the trench and pour concrete or pave. I feel for you. Through the years I've worked on all sorts of problems caused by man and nature. This one seems to have a little of each. Key is finding the angle of repose and depth to dood bearing
i will see what the Concrete stabilization company has to say. i can live with the driveway as there is no other issue with it. I'm just tired of the caulk expense every year. Reading you earlier posting on preparation and equalizing the depth to the width, I do not believe has ever been done by any of the contractors hired. One at a bid of 4.5K offers an 8 year warranty. While it's pricey i can guarantee I've probably spent 2x that in the last 8 years. So i will seer what mr. stabilizer has to say (they are very well known) and then likely quiz mr caulker a bit more with my newly gained knowledge and go from there. I will be reporting back. thanks again to all for their assistance
Well Mr. Concrete stabilizer specialist was quite impressed with himself. Sent me a nice informative book/brochure which had some Stroke and Poke in it, but informative if one read between the lines. It also had a tube of warming KY So after his evaluation and attempt to impress me even further with his laptop video at which time I said just give me the numbers. He obviously expected me to just rollover as he say's about 28,500 should do it I asked him what flipping galaxy he was from and said that ain't gonna happen. Did you see a big R for Rockefeller when you drove up my driveway? I actually got a little PO'd and told him you just wasted both of our times. Do you think I'm an idiot? At this point he knows he's about ready to head down that long driveway filling the joints with his butt as he slides LOL. So he quickly makes some adjustments on his laptop blaming a new bidding program while doing so. After a few minutes of fumbling, he says my apologies how does about 14K sound. I asked with what kind of warranty on the work? He responds with 5 years. I said pack your sh-t were DONE!!! So I still have the one guy at ~ 4.5K with an 8 year warranty which is obviously a lot more attractive but wanted your inputs before making a decision. my issue is time and this is just not in my experiences toolbox not to mention some physical limitations at 68 YO. One of you (SRT) mentioned liquid rubber. Again ZERO knowledge on this, what might the cost / advantages be over the Material the contractor is proposing to use DOW SIL CCS (contractors concrete sealant). I am attaching links to the spec sheets/ info on the DOWSIL product.
I've not used the product so can't really comment. I found here: https://www.dow.com/documents/en-us...-dowsil-contractors-concrete-sealant.pdf Leads me to believe it is more of a "bandaid" type seal and nor really for flatwork: DOWSIL™ Contractors Concrete Sealant is a one-part, low modulus, neutral-curing silicone sealant for use in non-specified, general concrete weathersealing applications. It is available in a wide variety of colors.
Joint Design DOWSIL™ sealants have been designed to perform when installed in compliance with accepted weathersealing procedures. Industry guides documenting in detail the procedures for designing weatherseal joints are available in publications such as ASTM C1193 Standard Guide for use of Joint Sealants. Some good examples are found later in this document. Dow has found that a few underlying principles are critical to consider in virtually all joint designs using silicone sealants. When considering the design of weatherproofing joints, the following basic points must be addressed: • In all cases, a minimum depth of 1/4" (6 mm) sealant/substrate bond is necessary to help ensure adequate adhesion. • In most cases, a minimum width of 1/4" (6 mm) opening is necessary to help ensure that sealant applied from a caulking gun will flow into the sealant joints. NOTE: In some cases where the sealant is used simply as a non-moving bedding compound and is applied to one substrate before both substrates are pressed together, thinner joint dimensions are acceptable. • One-part silicone sealants require atmospheric moisture to fully cure. Therefore, the sealant joint must be designed to ensure that the sealant is not isolated from the air. • For weatherseal applications where the sealant joint may be covering shims or setting blocks, dimensions may be less than the recommended ¼” (6 mm) if the application is relatively static, where expected movement is 15% or less. The dimensions should typically not be less than 1/8” (3 mm) to help ensure proper adhesion and sealant property build
I really think if mine I'd call the local airport or road maintenance division and find out who they are using for the rubberized material. Quick search yielded https://www.laymanpaving.com/crack-sealing/1869826
Keep in mind crack sealing either tube or hot pot needs to be done properly (routed, prepared by clearing debris and drying (compressed air).
Most important crack sealing will only keep water out and fines in the base course if properly done (depth to width ratio of material). It will not solve the underlying cause of the movement. My gut says thermal expansion contraction as the slabs (think sheets of ice) move about through the season. You have effectively a concrete glacier.creeping downhill very slowly. It sux the original contractors did not express their lack of knowledge.
BTW,
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. 
