Asphalt alligatored: Crush & Shape or Mill & Cap?

[square1]

I know it's an engineered base. I'll have to pull the prints and post the construction details next week.

The lot is somewhere between 15 & 17 years old so it has held up very well. If we could get 15 ~ 17 years out of the fix it would be awesome, but the budget has to be considered too.

 

[oosik]

Ha - Gary, some contractor from the "big" side of our state had one of those - grind, heat, remix, lay-it-down and roll it machines redoing a section of I-90 last year. It was such an attraction that it caused several fender-benders as folks rubber necked driving by the operation.

My friend - a highway engineer - suggested - - mill off 1.5 inches of the asphalt, spray a heavy asphalt seal coat followed by sand, roll the sand into the seal coat, when it dries brush excess sand off. This should last 5-8 years.

 

[Western]

I have a client with the same problem on one of his commercial lots. Agree 1k%, base has broke down. Cold planing down and replace is common, but doesn't address the fundamental problem. Same with a slurry seal or micro seal, sure it can make it "purdy" and in allot of cases (depending on the gatoring) can add several years to the life of the asphalt.

It will mirror, but who knows how long that may take. If it is an overlay that is still solid (firm to the 1st course), planing off may buy you some time. If it is gatered to the substrate, you can remove the old asphalt and test the substrate with a 3/8ths metal bar, if it only goes a 10th of a foot, then it is probably solid enough to replace and pack the asphalt (a patch). If the rod goes .20 of a foot and you see the fines have shifted, or water, then removing the base ( to solid earth/base and fortifying it, replace in lifts and pack, then asphalt.

Find out how water is getting under the lot and address the drainage, one crack that isn't sealed can ruin a good sized area with the hydraulic action from vehicles, freeze and thaw cycles. Crack sealing and seal coating are often passed on because of price, but it is far cheaper than asphalt repair/replacement over the long haul.

Just my:2cents:

 

[newbury]

Not to get too far off the thread but with "make do" or "jury rig" equipment is it feasible for a DIY go slow solution for asphalt driveway repair?

I used to work hot tar flat roofs so I'm a little familiar with asphalt.
I've got tractors and FELS to move materials. I can rig up a kettle and an endless supply of wood to heat it.

I was thinking I could tear a patch, say 10' x 10' out, remelt w/ a little fresh asphalt, pour and roll a kettle at a time.

I'm retired so time is not so critical.

 

[paulharvey]

Not to get too far off the thread but with "make do" or "jury rig" equipment is it feasible for a DIY go slow solution for asphalt driveway repair?

I used to work hot tar flat roofs so I'm a little familiar with asphalt.
I've got tractors and FELS to move materials. I can rig up a kettle and an endless supply of wood to heat it.

I was thinking I could tear a patch, say 10' x 10' out, remelt w/ a little fresh asphalt, pour and roll a kettle at a time.

I'm retired so time is not so critical.

Yes, you can DIY asphalt repair, but I wouldn't do what you're talking about. I would square cut the bad area, make sure the base is still in good shape. If not take a pick and scratch the base up and add some more, till the area is levell, 2" below the top of asphalt. Pack the area well with a tamp or maybe a sledge hammer. Get some cold tack/liquid asphalt and prime the base and edges of the cut. Of course do this in dry weather.

Get a ton of hot mix asphalt (Super pave SP-9.5 or S-3 Marshall mix) from a local asphalt plant in a pick up (put plywood in bed to allow clean up). Shovel asphalt into cut out area, leaving it 1/2" higher than surrounding area, throw some sand on it and tamp till smooth and level with surrounding area. If the asphalt gets too cold too work, heat with a weed burner.


Failing this, you can dig the cut the bad asphalt out, prime HEAVILY, and before it sets throw some 1/2" gravel (not base, gravel, clean stones) tamp the rocks firmly into base/tack. The retack, and another layer of gravel. We had a machine called a "Dura-patcher" that did this, it's not real pavement, but a chip seal (slag; bituminous surface treatment; whatever it's called in your area) patch.

 

[square1]

Here's the construction details. It's been kept well sealed and had cracks filled every fall.

The heavy sealer with sand added, then brushed sounds like a variation of "Chip & Seal" used on roads around here. I'd be worried it would track into the building on peoples shoes, especially on real hot sunny days.

 

[msmith1wa]

Before deciding on what repair method I would suggest some investigation.

Because your section is pretty thick I suspect that you might be having top down cracking. This can be cause by a few things one of them is just age and use. The other is the top layer has become un-bonded from the lower layer. When asphalt pavement is place there should be a coat of asphalt for tack coat between the layers. This acts as glue between layers.

Remove some of the top layer that is alligatored and see if the lower layer is also alligatored. If the lower layer is fine I would just remove the top 1.5" and replace with new. This can just be the bad areas to keep cost down or the whole thing if money is not a concern and give you a new looking lot for along time. If the lower layer is also cracked you should remove and replace full depth and place in layers using the thicknesses mentioned above.

 

[vtsnowedin]

Here's the construction details. It's been kept well sealed and had cracks filled every fall.
View attachment 378797
The heavy sealer with sand added, then brushed sounds like a variation of "Chip & Seal" used on roads around here. I'd be worried it would track into the building on peoples shoes, especially on real hot sunny days.

Well there is the source of the problem. The six inch layer of aggregate is not thick enough to spread the loads down to the common earth below during a Michigan winter and spring thaw cycle. What ever you do to the pavement will crack up again in a few winters. All previous suggestions still apply.

 

[square1]

The six inch layer of aggregate is not thick enough to spread the loads down to the common earth

Interesting input, thanks.
The best fix, cost no object (which is not the case) would be take down to the dirt, add more aggregate (how much?) before repaving? The budget isn't going to accommodate this, but I need to sell my recommendation to mill 3" & cap with (2) 1.5" lifts by presenting that full removal / replacement of asphalt is not going to give us a longer life relative to the higher cost.

If I mill & cap, regardless of the bottom layer condition, will the cracks return to the surface the same size or larger / smaller? I guess I'm counting on the settling of the original base / lower layer to be pretty well stable after 15 years.

Remove some of the top layer that is alligatored and see if the lower layer is also alligatored.

I like this idea. Do you have a suggestion for removing the top surface. A machine to rent possibly, or is it pick & shovel work?

 

[adirondackmtnman]

Interesting input, thanks.
The best fix, cost no object (which is not the case) would be take down to the dirt, add more aggregate (how much?) before repaving? The budget isn't going to accommodate this, but I need to sell my recommendation to mill 3" & cap with (2) 1.5" lifts by presenting that full removal / replacement of asphalt is not going to give us a longer life relative to the higher cost.

If I mill & cap, regardless of the bottom layer condition, will the cracks return to the surface the same size or larger / smaller? I guess I'm counting on the settling of the original base / lower layer to be pretty well stable after 15 years.

I like this idea. Do you have a suggestion for removing the top surface. A machine to rent possibly, or is it pick & shovel work?

If there are cracks through the base and binder finding their way to the top course, then yes, they will eventually repropegate through any new top course laid over them. The benefit of a fresh top course would be keeping moisture from reaching those lower layers, which would spread the cracks faster, especially in an area of heavy freeze/thaw cycles. New York State uses crack sealer on roadways where cracks have started to show through the top course pavement. This is followed most of the time by a mill and fill approach, where part of the top course is removed, and a fresh top of 12.5mm, 9.5mm, or increasingly a 6.3mm with polymer additives is placed. Most paving companies up here would, for parking lots, just tack and lay a new top course. I would recommend the milling approach, exposing fresh, non-oxidized asphalt just for adhesion purposes. Not sure they would have to take off 3 inches, but it depends how significant your cracking has become. Hope this helps!!!

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