Recommended Asphalt Testing

[SperlingPE]

I am a structural engineer with no background in asphalt paving. As part of a semi truck/trailer inspection/maintenance facility an asphalt parking lot was designed by our civil consultants. I am getting questions about what testing is required of the asphalt pavement. I am forwarding questions to our consultant, but want to educate myself a little before I get his responses.

What testing would you specify for this construction?

 

[eric1037]

At a minimum, I would get density testing and have somebody check thickness.

You could also get an extraction and gradation to verify asphalt content and aggregate. Maybe an independant Marshall numbers. You could even go so far as strength testing. However, that extent of testing is usually for roads. It depends on your experience with the supplier.

 

[Ron]

Agree with Eric1037. Pay particular attention to the type, gradation, and asphalt cement content of the asphaltic concrete. Your application needs a dense-graded mix with a relatively low asphalt content as excessive asphalt and tractor-trailer spotting/turning/staging don't mix well. You'll see significant scuffing of the asphalt and as compaction occurs from the weight of the vehicles, you'll see an increase in rutting and bleeding, if you have a mix with a higher asphalt content and smaller aggregate.

The problem with using a lower asphalt content (allowed because of larger aggregate...less surface area to cover on the aggregate), is that larger aggregate mixes tend to ravel and have a rough surface texture if not placed with a bit more care than the usual parking lot gets.

The in-place mix density should be as high as practicable, preferably in the 97 to 98 percent of laboratory density range.

 

[ACtrafficengr]

Good drainage and a quality subbase would help, too.

"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928

"I'm searching for the questions, so my answers will make sense." - Stephen Brust

 

[LCruiser]

Ron hit the nail on the head. The stresses on the AC will be extraordinary. Make sure you use a PG with a couple of steps higher upper temp rating.

 

[BigH]

May want to check softening point on the recovered asphalt - even on the asphalt at the plant. Depends a lot on anticipated temperatures of operation. India proved this out for me.