Concrete driveway rehab questions

Factual Questions
1

I’ve got a 10 year old concrete driveway that was poured in several roughly 10’x10’ sections. From the street, the first few sections slope down about 5 feet to the house, and the last section slopes back upwards a couple of inches to keep runoff out of the garage. The driveway’s also 3 sections wide, sloping slightly to the left to ensure drainage, maybe a 3" drop over a 30’ run.

But now it’s starting to need a little work. I do a lot of my own work, I just need a few hints about special tools, materials, and tricks of the trades …

  1. Expansion joint replacement.

The expansion joints between sections were installed with that bark-like quasi-wood quasi-felt stuff that’s been used for years. It’s about 3/8" thick and 2" tall.

Eventually that stuff get sodden, rots, and falls apart leaving a gap between each slab that gets invaded by weeds. That also lets water get under the slabs, contributing to settling.

I’m looking for a replacement joint filler, ideally some goo I could inject into the gap after I clean out the old expansion material & dirt. I could certainly go down to the local DIY Big Box and buy a case of outdoor caulk, but I’m looking for a product meant for, or at least commonly used for, this specific application.

  1. Uneven settling.

One point where 4 sections meet has settled 1/2" or so, resulting in a belly in the middle of the driveway which doesn’t drain. We get plenty of rain around here, and that near-perpetual 10’ diameter x 1/2" deep puddle is a problem. I’d like a controlled way to raise two sections on one side 3/4" and the other two sections about 1/4", restoring the proper slope.

It looks like these 4 sections are not separated by expansion joints; they’re just depressed score lines like most sidewalk “cracks”. The concrete below the score line has cracked as they’ve settled, and I’m predicting eventual problems with freeze/thaw as water works into those cracks. After I get them jacked into place I’d want to seal the cracks with something.

Jacking these slabs might not be DIY, but if anyone has any practical DIY experience, advice, or even cost WAGs for a pro job, I’d greatly appreciate it. Ditto suggestions on penetrating crack sealers.

Thanks in advance …

2

I’ve seen a sealant for filling in concrete cracks, except it isn’t DIY. I suspect that outdoor caulk would be just as good. You also might look for a type mastic which comes in strips … with peel-off paper; it is used between joints of concrete pipe. The boys at the concrete pipe place could probably help you find some. However, my 12-year old driveway has wood strips between the joints - no mastic or sealant at all.

As to the settlement, a very good method of lifting slabs is “mud-jacking”, if you can’t find a DIY way to do it. I think, though, that if you have more time and elbow grease than money, you could use a method which FEMA has been using to raise slab-on-grade houses above flood elevation. Theoretically, you could dig or tunnel under the slabs, install temporary "beam"s, and jack/shim until you got them level. When determining the location of the "beam"s, bear in mind that concrete takes compression much better than tension.

P.S. Love your sig.

3

The joint product you’re probably thinking of is ‘cutback’. However, you need to be able to heat it, as I recall, but newer products may possibly be used as a cold joint.

You may be best off to jack out the old crete to get to the problem underneath. I forgot to check where you live, but if in a northern clime, you will need to dig out the old material to a depth of a couple of feet and replace it with NFS (non-frost susceptible) soil, then compact the crap out of it before pouring the new slab(s). If in a more temperate climate, then you can disregard the NFS and just go with normal backfill, but still compact it well. That should get rid of the heaves and duck ponds.

Sorry, can’t help you with costs. Prices on material and labor differ wildly depending on area.

4

For settling problems at my new-old place, I used a company that does something called mud-jacking. I’ll let you look that up, but I’ll say they did a beautiful job re-setting my concrete at (what to me seems) an incredible price.

He recommended a product for sealing the expansion joints and cracks, but damned if I can remember what it is (yeah, having already bought and used it). It’s something sold at the big boxes, and it’s in the paint aisle near the caulk. You can’t miss it, and it’s specifically for concrete, and dries looking like concrete. You do have to underfill it with sand or something – I used (per the mud-jack guy’s recommendation) that foam stuff you wrap around pipes.

5

“Tremco Vulkem 45 One Part Self-leveling Polyurethane Sealant” is one such product. Easily done DIY (my Dad did it.)

As for the settling… a 10 year old driveway should not have settled that much. Mud jacking will certainly bring it back to level for under $1000, but the settling may return. Sounds like poor compaction under the drive or improper subgrade. Only way to fix it permanently would be to rip up driveway, excavate more deeply, and fill with better materials. I’d go with the Mud Jacking.

I can think of no good DIY options to level the slab.