Water stays on AC pavement

[stuus]

Hello all,

I am in charge of a paving project using standard 1/2" PG-64-10 Caltrans AC mix. The latest area was paved a couple hours before a rain event. This area is now uniformly covered with small puddles of water that doesn't drain off. The grades are around 1% and other areas of the project shows water draining off.

The only theory I have is that the oils from the curing, freshly paved asphalt mixed with the water and therefore it doesn't drain off.

Has anyone had similar experiences? Could I be correct regarding the oil or is there some other explanation?

Thanks,

 

[ztan]

Hi Stuus,

I doubt the theory of mixing oil with water. They simply don't mix with each other. Use a smart level to check the area where water stay to make sure it has the required slopes.

 

[gbam]

Is the standing water in a super transition? Some times there will be bird-baths created in these regions. Otherwise as ztan stated check the construction.

 

[Ron]

Sounds like you have "birdbaths". Has nothing to do with the oils mixing with water. Has to do with laydown technique, mix density, and (mostly) base variations.

 

[CarlB]

Yes I've seen some shallow puddles (1/8" or so) that seem to be caused by surface tension that wouldn't otherwise be there with older/less oily asphalt. Well they may still form but would spread out more maybe and dry out faster. Use a long (10' or so) straightedge to check, this method is normally in pavement specs for checking surface variations and whether they are within tolerances.

 

[BigInch]

Any oil wells nearby???

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[blueoak]

I don't think it is an oil/surface tension issue. Pretty sure water has a higher surface tension that oil wouldn't change. If your slopes are good, it may be more that the asphalt is still smooth and pretty clean which would allow for larger areas for surface tension to control. Throw some dirt on it.

 

[stuus]

Thank you everyone for your input.
Examination of the grades have shown that this was not a case of "bird baths".
Subsequent rain events have not yielded the same phenomenon, so I tend to believe that it was caused by the clean virgin asphalt that was still curing.