My apartment owner has resurfaced the parking lot.
It is some kind of black coating that was sprayed on.
The original parking lot was made using beach sand instead of normal sand.
So, it included a lot of shells.
I noticed that the shells deteriorated much faster than sand.
It resulted in many potholes.
Will that coating really last ?
Just curious,
Andy
Are we talking real potholes or small surface defects where small shells once were? In any case, seal coating that's applied has minimal filling capability. It's to make the surface look nice and give it some protection against deterioration, but not a lot. If you do a driveway with it periodically it makes it look nice and uniform, dark black, etc. But I doubt it adds a lot to the life of the driveway. How long it lasts depends a lot on the amount of traffic on it.
I can't tell how long it may last but know that asphalt is a mixture of sand, rocks and tar. The resin/tar binder content is low, maybe 10% and material has voids where moisture can seep in and freezing and thawing degrade the asphalt.
When I had my driveway repaved a couple of years ago, rain would just seep right through. Coating helps seal these voids and its efficiency depends on how much is used. Guy that put mine in wanted to come back and coat it every year and I let him do it the first year but it was chincy and now I do it myself with coatings that can last several years.
I read some advantages of shells in asphalt, apparently increasing the wetting of sand and rocks but I would think that shells being calcium carbonate would erode faster.
Seat coating does two things: it makes the surface look good and it fills the microcracks. Microcracks allow water to penetrate. In warmer climates, that doesn't matter a whole lot. In cold climates, it prevents water from freezing, which preserves the integrity of the asphalt and definietly extends the life.
Depends what coating he used and where you are. There are coal-tar emulsion coatings, asphault coatings, and several different asrylic coatings Some stand up well, some not at all - and it depends when and how they are applied. They all work best on perfectly clean (well swept) surfaces with no oil contamination - applied to a dry surface within a specific temperature range, and not rained on for 24 or more hours.
The coating will do nothing for potholes - they need to be "properly" filled first.
How do you define 'last'? I haven't been paying strict attention but around here commercial parking lots and so forth are resealed every few years.
Thanks for all the responses.
Andy
They absorb oil well which is good for keeping the whole thing stuck together but it's bad in the sense that it costs more for the extra asphalt that soaks into them. And they are not very hard so they wear faster on highways but in a parking lot it may not be a big deal. If they are still shells the odd shape may have made it more difficult for them to get fully coated so they stick well in the original mix but I wouldn't think it would make much difference when you are spraying a seal on the top. The life is going to depend on how much oil was sprayed on, what type of oil, etc. as well as what's under it. It's unlikely it will last more then 5 years in terms of effectiveness and might only last 1 or 2.
Typical sealant used on parking lots, driveways, etc is not oil. I've never seen oil used, except on dirt roads to keep the dust down.
Oil is the generic term for petroleum products used in the paving industry. The industry calls what is in the AC mixes and what's sprayed on roads "oil" all the time. Often people talk about "oil content" even though the more correct term is "asphalt cement content", etc.
Maybe in your world, but not mine. I've dealt with seal coating companies for condo complexes, home driveways, etc. Never heard them call it oil. It's like calling plastic, or epoxy or similar oil, because it's made from it.
This page discusses three types of asphalt sealcoating materials:
Coal Tar Emulsion Asphalt Emulsion Oil Based sealers.
It specifically notes that the oil based sealer "is primarily used by asphalt paving contractors because it is located at the asphalt plants. Not many professional sealcoating companies use this type of sealer due to the inherent limitations.
Is it possible that you have been dealing with "professional sealcoating companies" as opposed to "asphalt paving contractors" which would have meant that the oil based sealer was left out of the mix?
(Granted, I doubt all sealcoating options are generically referred to as "oil" since it appears to be a specific type of sealcoating material.)
te:
Good find.
In addition to saying not many pro sealing companies use it, they say:
"An oil based asphalt sealer, also known as "asphalt rejuvenator", is co mprised of asphaltic chemicals based with an oil composition. This asphalt sealing material has the same limitations as Asphalt Emulsion sealer. Becau se it is a petroleum based product, it does not protect against petroleum products. Also, this material has a distinct odor that last for days. Anoth er limitation to oil based sealers is that it takes a week to cure properly before line painting can be accomplished. Commercial property owners consi dering oil based sealer must take this into account. "
Doesn't sound like the stuff under discussion, ie what would typically be used on a parking lot.
My world is 37 years in the Highway construction industry as a professional engineer and manager specializing in paving, materials design and management, both asphalt and concrete, laboratory testing of liquid petroleum products and AC and PCC mixes with presentations at international conferences and consulting with local, national and international groups on their paving problems. "oil" is a very common term used in the industry for the many and various forms of petroleum products. Perhaps your local experience with seal coating driveways may not encompass as broad a view of the totality of the industry.
While not intending to hijack your thread, this is probably the best place to ask:
What sort of monies ($US) are involved in "repaving" a parking lot? And, is this expressed as some_fixed_cost + cost_per_unit_area? Does the asphalt contractor also take on the demo and regrading?
A local organization is looking at purchasing a modest sized building with a large parking lot -- primarily for the off-street parking that it provides.
However, the lot is in terrible shape -- lots of deep pot holes, torn sections of pavement, etc. One would almost think it easier to rip up the existing asphalt, regrade it and then lay *new* asphalt!
I've tried to point this out to the interested parties but I suspect they are so enamored with the AMOUNT of parking space that they are too eagerly overlooking the cost, down-the-road, of making that space truly usable!
It would be nice to have some general idea as to whether this is tens of thousands of dollars or *hundreds* of thousands!
Paving over a subsurface that needs repair is throwing money away. Every crack and pothole will reflect right through the new asphalt. Far less labor and cheap material to rake up the old surface, roll down new roadbase and cover.
Check back with me in a year or so.
My street was a mess of patches and cracked asphalt. My town was going to mill the surface and then lay asphalt. They changed their minds and milled only the ends where my street meets the cross streets and then "raised" the rest of the street with about 3 inches of fresh asphalt. They then came back and added aprons at each of our driveways to eliminate the lip.
We'll have to see how this works out as time goes by. The reason it may work is that there are only 7 houses on my street and it is rarely used as a through route - usually only when someone is lost. For now, I'm loving the new road.
Isn't that what I said: One would almost think it easier to rip up the existing asphalt, regrade it and then lay *new* asphalt!
Which leaves the original questions: What sort of monies ($US) are involved in "repaving" a parking lot? And, is this expressed as some_fixed_cost + cost_per_unit_area? Does the asphalt contractor also take on the demo and regrading?
It depends on what the problem was. If the only problem was that the original asphalt had broken down and looked like croc skin, then you may get away with it for a while. The problem is that unstable asphalt doesn't make the best base.
If there are lots of large cracks and potholes, those will show through the new surface quite quickly. Same principle as painting without prep.
Yes, I was agreeing with you.
I would expect any reputable paving contractor (not sealcoat company) would handle the whole job.
Cost such a local thing, you are going to have to talk to a couple of local contractors to get quotes. Does have the equipment and crew or does he have to sub out some of the work? How hungry is he?
How he comes up with his number is kind of immaterial. You don't know if he has a large nut to cover or brings on crew and equipment as needed. He's also not going to give you a quote without looking at the site. There's all sorts of things that need to go into the quote - access, drains, curbs, light poles, off site parking for crew and equipment, easments, permits...
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