Asphalt storage pad

[TheGumpster]

I'm extending my driveway (12' wide) by 17 feet so I can park my 33' Forest River 5th wheel on it for a few days before and after our trips. We have an offsite storage facility for long-term storage. The dry weight is 10,000 pounds, axle dry weight is 8,000 pounds, hitch weight 2,000 pounds. It is a dual axle. When parked, we will have 2x12's (2' long) under the rear stabilizers and under the front jacks. I'm getting quotes for the asphalt. One contractor says 4" crush run and 2-1/2" hot mix will do the job. The other contractor says 6" crush run and 3" hot mix and is using the "better safe than sorry" argument. Where can I get an objective opinion on how thick the asphalt needs to be?

[CavemanCharlie]

I still don't get why the OP can not just use gravel ? He only wants to park on it once and awhile.

Where I am the road I live on is gravel, my driveway is gravel, most everything is gravel.

It's a lot cheaper then either asphalt or concrete.

Now, some stupid city ordnance may get in the way. I don't know about that.

It just seems like you are all trying to do things the hard way.

[hawkeye-08]

Here where we live, asphalt is considered temporary (does not increase home value) and concrete is considered permanent and does increase value. We got a good deal on some asphalt and did a 100' by 24' driveway. We love it. I need to seal it again (been more than 5 years) but otherwise wonder why we did not do it sooner (money is that answer).

For our parking places for the travel trailers (we have dads and ours at our house), I plan on putting concrete pads where the tires are and perhaps the tongue jack. One spot will get crushed gravel for the rest, the other left in lawn (just mow over the concrete pads when the trailer is not there.)

[Cummins12V98]

Aron wrote:
I'm an engineer with some experience designing highway pavements. In general, 10,000 lbs is fairly light for a pavement design, so pretty much any of the suggestions in this thread would work (including either of the OP's original pavement and gravel thicknesses), especially if its only carrying that weight occasionally. Its possible that parking a static load in one spot for a few hot days could create a bit of a divot (asphalt is basically a mix of tar and gravel, and tar flows in heat), but I wouldn't think it would be bad. It's really the gravel that provides the load carrying support, so don't skimp there. There's probably not a huge cost difference between the 2.5"/4" design and the 3"/6" design, so I would probably go with the slightly thicker one just for added assurance.

Speaking of gravel, the only suggestion in this thread that I wouldn't follow is the use of pea gravel. It's the angular interlocking characteristics of compacted gravel that provide the weight bearing support; over time, rounded pea gravel would tend to flow away from the concentrated weight points under the tires. I suppose it could work under concrete if the concrete is thick enough, but under asphalt it would probably provide poor support.

If you are referring to me I never suggested using pea gravel for substrate under asphalt. Yes it works VERY well for backfill in ditches and under concrete slabs.

[BCSnob]

We stored a pop up trailer on black top paved area (not our parking area) and in a few months there were depressions under the tires. What is the point in paying to have paving put down for a parking spot that you must then protect with boards?

[Aron]

I'm an engineer with some experience designing highway pavements. In general, 10,000 lbs is fairly light for a pavement design, so pretty much any of the suggestions in this thread would work (including either of the OP's original pavement and gravel thicknesses), especially if its only carrying that weight occasionally. Its possible that parking a static load in one spot for a few hot days could create a bit of a divot (asphalt is basically a mix of tar and gravel, and tar flows in heat), but I wouldn't think it would be bad. It's really the gravel that provides the load carrying support, so don't skimp there. There's probably not a huge cost difference between the 2.5"/4" design and the 3"/6" design, so I would probably go with the slightly thicker one just for added assurance.

Speaking of gravel, the only suggestion in this thread that I wouldn't follow is the use of pea gravel. It's the angular interlocking characteristics of compacted gravel that provide the weight bearing support; over time, rounded pea gravel would tend to flow away from the concentrated weight points under the tires. I suppose it could work under concrete if the concrete is thick enough, but under asphalt it would probably provide poor support.

[spoon059]

westend wrote:

Normal driveways in my area are typically 4" thick asphalt over 6" of concrete

Did you mean 4" of asphalt over 6" of base?

Yes, I misspoke and fixed it. 4" asphalt over 6" of COMPACTED GRAVEL... Sorry about that! Thanks for catching it!!!

[westend]

Normal driveways in my area are typically 4" thick asphalt over 6" of concrete

Did you mean 4" of asphalt over 6" of base? There is little reason to place 6" of concrete under an asphalt driveway. The 6" of concrete would support any typical residential loads.

FWIW, I place a few aprons/yr. in front of garages that have existing asphalt driveways. This is due to block foundations located outside of poured garage slabs. As the owners drive over this hollow block space and the asphalt crumbles, holes appear. For garage slabs and those aprons, I will order fiber reinforced redi-mix (5K lbs) and reinforce with cross-tied 1/2" rebar. I don't get any call backs from placing in this manner. IMO, concrete, if placed correctly, is superior to asphalt in most regards.

[Slownsy]

I will only say that the person saying not to use reo in concrete has absolutely no idear, use reo and proper crack joints so it can't move op or down on a proper playsed base. Retired builder have many a discussion re plasing concrete with know it alls and also had to take op and replace driveway to units not playsed properly, by the way reo is not ment to be playsed in the center of concrete but about 1/3 from top playsed on supports so concretes can't step it to bottom.
Frank.

[Cummins12V98]

Sam Spade wrote:

Cummins12V98 wrote:

Pea grave once placed is 100 percent compacted and provides great drainage.

Maybe we have a terminology problem here but Pea gravel does not compact AT ALL as evidenced by the "great drainage" and allows rather rapid water movement under your slab.

When water moves, it takes "stuff" with it. If you do this on a grade where there is heavy and frequent water flow it probably is just a matter of time until the underlying soil starts moving with the water.

If you don't have a lot of water movement, you may not have a problem.

Did you read what the conditions were where I mentioned using Pea Gravel? Every condition I mentioned using Pea Gravel is completely acceptable and is a big labor saver. 35 years under my belt in the Construction Industry building many Tenant Improvements and ground up buildings including the site work.A little creativity sometimes can save BIG $ and be a better product for the conditions.

YES once placed Pea Gravel is at 100 percent compaction.

I think you are trying to pick fly sh!t out of the pepper bowl!

[bid_time]

It seems if pea gravel was such a tremendous material they would use it under major roads and highways. But they don't, they only use in trenches that are confined on all four sides. What they use under major roads is well graded gravel compacted to a minimum of 95 percent. Go figure. At least that's how they do it in the north.

[Sam_Spade]

CavemanCharlie wrote:
Um, if you are going to only park it there once and awhile why not use some sort of porous material ?

That might be a reasonable option if you understand the limitations.

Water and general usage will remove the loose material over time.
And if you are in the North or Upper Midwest, the material will heave due to freezing and might be REALLY soft a few weeks of the year.

[Cummins12V98]

First I assume that the sub grade is solid with my suggestion for a RV pad with 6" pea gravel and 4" of 6 sack concrete with wire mesh. I would suggest deep grooving the concrete for crack controll also.

Pea grave once placed is 100 percent compacted and provides great drainage. I have used pea gravel to backfill utility ditches for example and required no compaction. I have never had a ditch show thru a parking lot. Under asphalt 5/8 compacted crushed is required because asphalt is not as stable as concrete. Pea gravel is a good substrate for sidewalks also. Same for interior building slabs. Have also used on a big Safeway distribution yard with 8-10" of concrete over the pea gravel with steel rebar. I also use it to backfill ditches inside buildings for plumbing ditches. Fills around pipes without causing damage.

[rhagfo]

Cummins12V98 wrote:
Pour 4" of 6 sack concrete with 6x6 wire mesh over 6" washed pea gravel. Pea gravel requires NO compaction, it goes down at 100 Percent.

Poured my RV pad like that 15 years ago and it still looks great.

Cummins, please explain why the use of pea gravel? I ask because when DW did Day Care we placed 6" of pea gravel under the play equipment as it DIDN'T pack, if you walked through it you would sink into it.
By itself it won't compact, why is it used so much as a base under concrete? I assume this is an expert subject for you.

[CavemanCharlie]

Um, if you are going to only park it there once and awhile why not use some sort of porous material ?

All this asphalt and concert is just more hard surfaces that allows polluted run off water quickly into lakes, streams, and rivers.

[Sam_Spade]

Cummins12V98 wrote:
Pour 4" of 6 sack concrete with 6x6 wire mesh over 6" washed pea gravel. Pea gravel requires NO compaction, it goes down at 100 Percent.

Poured my RV pad like that 15 years ago and it still looks great.

You got lucky.
6X6 mesh isn't enough. 4X4 minimum and I use 4X4 rebar.

Wet ungraded gravel is better than pea gravel because there is less air space.
They use CA-6 for roads for a reason; almost no air space.

They use reinforced concrete when strength is important.

I'm amazed that someone advising NO reinforcement in concrete in CHICAGO is still in business.