Parking Lot Repair and Re-Sealing

Sealmaster makes good products, the secret is sand in the asphalt emulsion which provides good filling quality and wear....The other half of the equation is the skill and knowledge of the person doing the job, how big the cracks are, and the general overall condition of the surface....

http://www.sealmaster.net/asphalt-sealant.shtml

I know nothing on the topic (not a good way to start a reply !), but you didn't state a location. Reason for asking is that I'm wondering if there's a better time of year to do such work. ie - if you can hang on a few months, can a better job be done in Summer than in Winter ?

Sounds like you have given the issue some thought, and will have (or will be) getting several contractors to quote. Any reputable company will not be offended at you doing so, and your checking up on satisfied customers.

SolarEagle has given a link to a product, and that's useful. I imagine that how the job is done is as (possibly more) important

If you can do so, a photograph might enable some of CR4's experts to give a rough assessment with regard to the scale of the job. Sorry, but I'm just offering a few cents so I can read a little and learn on this topic. Finding a decent company to do this job (and ensuring the contract details etc are solid) may be a more important than the specific material they use.

Best of luck, I'll be interested to read how this progresses.

I've watched crews patch cracks and seal asphalt parking lots. That qualifies me to give advice.

Hire a reputable contractor.

I've watched Emergency Ward 10, but Del still refuses the ointment I suggested. He'll be sorry when it drops on the floor. The ointment, that is.

In this day and age, there are more cowboys than the 1880's. The big question here seems to be about how to identify somebody who can do the job to the quality required. If I wasn't busy laying 5mm of blacktop on some poor person's driveway I'd put in a bid.

I would dig out the cracks deeper, with vertical or even slightly overhung sides to get a grip on the "spline" patch. The best material would depend on the existing pavement and local climate.

The area is Northern Illinois. The work would be done in the summer.

I was involved in a paving project recently at work and was not liking everything I saw. So I did a little research online and learned a very little bit.

My project was to remove and replace the foundation and asphault and based upon what I read, it is the best way to go no matter the problems with your current pavement.

That being said, repairs can extend the life of your pavement depending on the level of degredation. The big thing to look for is water intrusion, if you have large areas where it looks like drying clay (football sized chunks) that are as thick as the pavement itself the cracks between will allow water to get under and wash out the foundation. If this is large regions you might be better off replacing the entire surface and foundation.

If you have small areas that have the above condition you can get away with digging up and patching those regions only.

Fresh asphault has some give to it and it will flex under a load, when it get old and the solvent dries out the stiffening material will crack leaving the drying clay blocks. The large blocks of cracked asphault allow water to get through and wash out the foundation. The older your asphault is the less help a sealant will do because only so much of the fresh solvent will be able to penetrate and add flex to the material, too much solvent on top and you dissolve the top layer (still without penetrating where it needs to go).

There are many other models of how asphault wears out, but this is what I think is most common for a parking lot or other low traffic area.

My bottom advice, get a friend from the local road crews to ask one of their proffesionals to have a look. A quick lookover will tell an expert all they need to advise you.

Advice to all who are overseeing a paving project: you don't want to allow asphault to be tossed in the air (with a shovel) or overworked with a rake. This allows the granuals of aggregate to cool too much and not bond. You wind up with a porosity that allows water to penetrate and a poor bonding of material.

Drew K

There is a lot of IF's involved here.

A lot depends on what caused the cracks and their magnitude. Cracks can be caused by thermal expansion and contraction of the asphalt due to temperature changes, that range from maximum to minimum.

Or,

from vehicle wheel overloading.

Or,

from inadequate asphalt section (thickness and type).

Or,

from inadequate pavement subbase section and type.

Or,

from unacceptable soils (subgrade) underlying the pavement, such as clays and silty soils.

Or,

inadequate drainage present, where the accumulated water finds it's way into the subbase and subgrade and isn't drained away, thereby weakening the entire pavement section.

Or,

from overall age of the asphalt pavement and it's inherent strength.

If anything, proper preparation of the cracks is essential, by blowing the dirt and stones out of the cracks.

A lot will depend on the size of the parking lot and the eventual principal costs to seal and seal it. If it is large, then a considerable amount of funds are involved to rehabilitate the parking lot. If this is the case, I suggest that you hire a local Professional Engineer who provides Civil Engineering services to evaluate and make recommendations how to rehabilitate the pavement. The engineer can also perform construction observations to insure that the contractor (if one is hired) conforms to the engineer's recommendations. In this day and age of paving contractor scam artists and fly-by-night operators, it may be a good insurance policy towards getting exactly what is needed and not needed. Never ever hire traveling contractors that are not from your locale....they are usually known as 'Tinkerers', and are notorious scam artists using unacceptable or weakened materials and ineffective construction practices and techniques. BEWARE OF THEM AT ALL COSTS!

signed,

CaptainMoosie, Ph.D, P.E.