Type A asphault

Old 10-27-06, 06:12 AM
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Type A asphault

My paving contractor used this on my driveway.

2 questions:

1- it seems very permeable - it soaks up water like a sponge. Is that normal? I worry that the base wasn't adequately prepared to drain all the absorption, and I worry about repeated freezing cycles with trapped water in all the hollows.

2- he failed to pitch the lower corner of the driveway propoerly, allowing for puddling by the garage. He wants to try to re-heat the area and re-compress it. We're talking about an area perhaps 4'x4'. Is that a viable option? Otherwise he'd cut and patch - something I'm not thrilled about for my brand new driveway.

FWIW, I'm in the northeast.(Temps currently have highs in the 40s-50s with lows in the 30s.)
Old 10-27-06, 08:14 PM
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Wet soil and weak soil can disturb gravel base of driveway, which should slope about 1/4"/FT for drainage or be virtually flat. This prevents water from puddling on asphalt. Puddling is not good.

Type of soil determines how driveway base is prepared. Some soils are very weak. Top soil is usually removed and soil compacted. If soil is a type that does not drain well when wet, drain tiles are recommended. A special geo-tech fabric is recommended over soil to keep it from getting mixed with gravel. 6-10" gravel is used for the bed depending on soil type and traffic.

Gravel and binders are mixed in with asphalts. There are different types of asphalt, depending on mix. Highways mix in big gravels which make the asphalt much stronger than driveways which have smaller gravels. The smaller the gravels, the weaker the asphalt. Typically the first layer of asphalt has larger gravels than the top finish layer. Thickness is determined by the base.

Depending on type, asphalt should be sealed to keep water out of pores. The first sealing takes place after the first year and then every two to three years. Too much sealer will build up and peel and crack and look unsightly. The sealer will wear off in the high traffic areas, so it should be applied much thinner to the non-traffic areas.

Not all asphalt contractors are created equal. Low spots and puddles are an indication that proper base preparation was not done.

"It soaks up water like a sponge." There are newer asphalts available that are water permeable and are meant for water to pass through. Yet, "puddling by the garage." It would seem reasonable that reheating and recompressing the asphalt that is atop other issues will not resolve the problems. An asphalt driveway or highway is only as good as the base beneath.

More information about Type A asphalt's mixture would be enlightening. For instance, if it one of the newer asphalts that have recycled rubber and meant to be water permeable like those for track teams, sealing would not be recommended. In addition, details on driveway construction, soil type, drainage, etc. might help.

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