I read that driveway fabric can help prevent new cracking when putting an asphalt overlay on top of an existing asphalt driveway networked with little cracks ("alligator"). Can this be done DIY? If so, would I fill the depressions with asphalt patch first?
What's the difference between driveway fabric and landscape cloth (if any)? I have a whole lot of landscape cloth left over from a project and I wonder if I could use that.
Here's a general description of petro-mats:
The greatest source of damaging water in road structural sections is precipitation infiltration through pavements. Most pavements do not have adequate drainage systems to quickly remove infiltrated water. If a pavement base is saturated as little as 10% of the time, the useful life of that pavement will be reduced by 50%. The Petromat fabric, when saturated with the asphalt cement tack coat, becomes a moisture barrier in the pavement, minimizing surface water infiltration. The American Association of Highway and Transportation Officials (AASHTO) 1993 flexible pavement design methodology gives a substantial structural credit to unbound roadbase materials when they are well drained and not allowed to become saturated. By minimizing water infiltration, the Petromat System moisture barrier will keep the road base more well drained and will therefore maximize the structural strength of unbound roadbase materials.
I think geotextiles were initially used in pavement as a weed barrier under the gravel sub-base, but then they evolved from there.
Best Answer
I talked to one of the petro-mat sellers and found out that the standard petro-mat needs a liquid "tack coat" poured down before the geotextile is put down. Typically the fabric is put down with a special machine. To put it down manually would ideally involve four people, one standing at each corner, because if folds or wrinkles form, the piece has to be thrown out and you have to start fresh. One could do patchwork, with reasonably sized sections, to make it more workable. But the tack coat is very hot asphalt with no gravel, I think -- which is beyond this DIYer.
Some more googling led me to another type of petro-mat that doesn't required the initial tack coat. For this one, you just clean the driveway thoroughly, fill any cracks at least half an inch wide, and lay it down. It sticks to the driveway and stays put nicely while the asphalt is being put down. Description:
I plan to make an appointment with a residential paving service to have a new layer of asphalt put on my driveway. The previous weekend I will clean it thoroughly, use a knife to clear out the bigger cracks, fill them with the DIY crack treatment, and then the day of the asphalt appointment, I will lay out the glass grid geotextile and stick it down. I'll let the asphalt people do their regular thing.
I think that the occasional small depression should get evened out through the normal paving process, so I don't plan to do anything to those spots in advance.
The challenge now is to get a small piece of glass grid. It comes in very large rolls since this material is not currently marketed to the residential consumer. However, one of the sales people connected me to a paver three hours away who works with glass grid, and he has agreed to send me a remnant next time he has some leftover from a big parking lot. (None of the pavers in my area have the slightest idea geotextiles even exist.)