Asphalt driveway damage / repair

[dgeesaman]

It doesn't appear to be distressed enough for that to be the case. The pavement you have is keeping the base from mixing with the silt below but it isn't strong enough to avoid cracking when a truck goes over it when the base and subsoil is saturated in the spring.
When building new an eight inch layer of clean sand does about the same job as a geotextile fabric and often costs less. Which to use comes down to the cost of excavating out the extra eight inches or the strength and water level of the soil below.

Thanks. One last question: I'm sure the heavy trucks sometimes wander right to the edge or off of it, which could easily start cracks at the edges that would then grow inward. Can we do anything to insure against that method of damage? Does it help to have the finished surface above the grade by a couple of inches?

Or is a properly built driveway/road going to be equally durable out to it's edge?

 

[paulharvey]

Thanks. One last question: I'm sure the heavy trucks sometimes wander right to the edge or off of it, which could easily start cracks at the edges that would then grow inward. Can we do anything to insure against that method of damage? Does it help to have the finished surface above the grade by a couple of inches?

Or is a properly built driveway/road going to be equally durable out to it's edge?

A typical road calls for the base to be full thickness 6" past the edge of asphalt. This helps support the edge of the asphalt. The sod is held down approx 1" below the top of the asphalt to avoid trapping water on the roadway, while at the same time avoiding excessive roadside dropoffs.

 

[dodge man]

I work for a civil engineering company and have density tests on roadway. We never test the edge for the roadway for density because there is nothing for the roller to roll against. If there was a curb or something to restrain the edge of the asphalt as the roller rolled along the edge, then the density would be good, but with out something to restrain that edge, the asphalt just squishes out and you don't get good density.

 

[dgeesaman]

That suggests the road should be extra wide - if the heaviest vehicle runs to the edge of the driveway, it's not going to hold up either. And once a crack starts it always grows. I think that may be a factor in my driveway problem.

At the end of the day, I think I'll have in mind to get quotes for work knowing 1) the heaviest vehicle load 2) the widest heavy vehicle and 3) expected life. It seems nothing will be comparable unless those are considered. Then if I'm having stuff delivered I can specify a reasonable limit - more axles, less in the bed, etc and be much more aware of when the soil conditions are most risky too. At this point there is extensive cracking and I think the cracks are growing regardless of soil condition.

I'm not a civil but a mechanical. I don't expect to review the designs but at least I can hope to communicate a sufficient set of specs. Or maybe dig deeper - this is a huge investment - if there is good reading material you suggest I'll go bone up on it.

 

[vtsnowedin]

Six inches is cutting it a little close considering the experience level of the average road worker today. A better plan is to place your base a foot wider on each side of the pavement edge and compact it as well as the available equipment can do it. If your in cut that is no problem as the old ground will hold against the compactive effort. In fill, four to one side slopes or flatter are the best bet, but if you have to go to two to one then they add a foot to each side to help hold against the compactive force and to provide a strip to hold the guard rail posts.

 

[paulharvey]

I would download your local city/county/dot specifications for driveway Construction. They probably don't regulate what you do outside of the ROW, but they will have standards of how they do it in the ROW. If you have a lot of truck traffic, consider using the spec for "commercial driveway". In Florida, it would be 6" of 3000 psi with wire on compacted subgrade, if using concrete; or 1.5" of Sp-9.5 on 10" of LBR100 limerock, compacted to 98% modified proctor (100% of standard proctor).

Edit: residential asphalt would be 1.25" of sp-9.5 on 6" of rock.

Re-edit: both specs assume a firm subgrade or native ground,

 

[vtsnowedin]

That suggests the road should be extra wide - if the heaviest vehicle runs to the edge of the driveway, it's not going to hold up either. And once a crack starts it always grows. I think that may be a factor in my driveway problem.

At the end of the day, I think I'll have in mind to get quotes for work knowing 1) the heaviest vehicle load 2) the widest heavy vehicle and 3) expected life. It seems nothing will be comparable unless those are considered. Then if I'm having stuff delivered I can specify a reasonable limit - more axles, less in the bed, etc and be much more aware of when the soil conditions are most risky too. At this point there is extensive cracking and I think the cracks are growing regardless of soil condition.

I'm not a civil but a mechanical. I don't expect to review the designs but at least I can hope to communicate a sufficient set of specs. Or maybe dig deeper - this is a huge investment - if there is good reading material you suggest I'll go bone up on it.

Actually Dgeesaman I think your driveway is in pretty good shape for it's age and could last several more years with no attention whatsoever. If you are fussy and want it to look perfect then it comes down to how much you want to spend on perfection. Being a cheap SOB I'd probably drive on it as is for years until you needed to fill pot holes with patch to drive over it without spilling your commuter cup of coffee.

 

[dodge man]

One thing to keep in mind is asphalt is considered a flexible pavement. Its designed to move up and down. When it move up and down to much in too short of a span, thats when it cracks, or as the driveway ages, it gets more brittle and starts to crack.

 

[newbury]

Good thread because I've the same problem developing.
I've a driveway/parking area about 180 yards long and about 1,000 sq yards in area (SWAG). It's in Mississippi thus USUALLY very little frost problems, it's fairly well sloped so little standing water. But I am getting areas that are "cracking", mostly around the edges.

Chip and tar, what we call Chip and Seal or "slag" will flex with the movement and is a good choice if, and only if, there's people around who can do it cheaply. I think for 50 lane miles, we where paying $2.40/ square yard, and a 1" thick over lay runs from $5-7.50/sy (large scale quantities, home owner price is probably double that).

The Grafco crack sealer is a (roughly) half rubber half asphalt that will seal cracks and also hold them together. It had to be heated in a kettle or heated crack sealer machine (approx 400-500 degrees), but there are some more consumer friendly products. If the entire (or a good percentage) 1000 lf of the drive is alligator cracked, the chip seal is a good option, and works well with an eventual asphalt overlay.

Did you mean Crafco crack sealer? Request Rejected
Is that much the same as the "tar blocks" mentioned below?

I have a 1200' driveway that was alligatoring on the edges sometimes up to two feet in. Our situations are different in that no dump trucks or gravel trucks come on the driveway, just my 16,000# camper and my dually. This was neglected for years. I have a pretty decent base, I think so that wasn't a concern for me.

As suggested by someone on this site, I went to Lowes and got tar blocks, heated then to melt them on a 40-60,000 BTU burner, put that in something called a pour pot, then poured the liquid on the bad areas and my wife used a long handled ice scraper to smear it into the cracks. It is a rubberized darker color than the rest of the drive but works in my situation where light traffic is involved.

My ideal fix would be to pick up the to two inches and start over, but this is cheaper, although may not work in your situation. Cost for me was 75$ for the pour pot, $350 for tar, $100 for LP.

Are "tar blocks" the same thing as what I used to put in the hot tar kettle when I used to work flat roofs? We would then mop it on the felt.

That is a good way to get to the bottom of the problem. I would only add that instead of adding gravel I would add just inch and a half minus concrete stone. The mix that comes out of the grinder already has too much sand in it and adding gravel which is a good mix of sand and stone doesn't have any extra stones to give to the ground up sand.
I've spread on as much as 0.17 tons of stone per square yard (a layer three inches deep) and had them mix it in with the second pass of the reclaimer. Overlaid with three inches of hot mix 2 binder 1 top and you get a road stronger then many of your state roads. Don't forget the drainage if needed though. Water is the worst enemy of a road.

What I had feared doing was to section off an area, dig it out, put down base, repave on a retired do-it-myself basis.

I figured getting a contractor to do it would be big bucks I could spend elsewhere (grapple, QA, log arch )

 

[Streetcar]

Good thread because I've the same problem developing.
I've a driveway/parking area about 180 yards long and about 1,000 sq yards in area (SWAG). It's in Mississippi thus USUALLY very little frost problems, it's fairly well sloped so little standing water. But I am getting areas that are "cracking", mostly around the edges.

Did you mean Crafco crack sealer? Request Rejected
Is that much the same as the "tar blocks" mentioned below?

Are "tar blocks" the same thing as what I used to put in the hot tar kettle when I used to work flat roofs? We would then mop it on the felt.

What I had feared doing was to section off an area, dig it out, put down base, repave on a retired do-it-myself basis.

I figured getting a contractor to do it would be big bucks I could spend elsewhere (grapple, QA, log arch )

Crafco is the brand name of the crack sealer
The tar blocks at lowes are the same as roofing tar.
The OP has a new driveway that was severely under designed for the loads it carries .
Can you post pictures of the Mississippi driveway.
If your driveway has been functioning and is showing age, it will be a different repair method