Asphalt Compaction Issue

[NNDEV]

Can anyone tell me where I may find a written standard that allows for the adjustment of a marshall factor when nuclear testing the density of asphalt? My understanding is that the marshall factor may be adjusted to give a more accurate reading when testing a 1.5 inch lift of asphalt. I was told that the proctor of the gravel below needs to be accounted for. Any insight would be appreciated.

 

[Zambo]

I prefer cores to nuclear testing so don't know anything about an adjustment. 38mm isn't very thick for a layer of asphalt, you need to be careful when compacting as there is a possibility of heat loss and therefore compaction difficulties.

 

[Hardball1911]

The Marshall factor should have been determined by the designing engineer for the mix. It should be available on the mix design information, and if it is not, you can contact the mix supplier for this information typically.

Most nuclear density gauges have a thin lift setting of some sort. It is best to contact the manufacturer of the gauge for instructions if you do not currently know how to set this up.

I hope this helps.

 

[ncarolinageo]

Depending on the manufacturer and model of the nuclear density gauge you are using, there is sometimes a correction factor that can be put into the gauge itself. More specifically, I know that the Troxler 3440 will do the correction for a "thin lift" of asphalt (which I believe Troxler defines as 2 inches or less) by having the user input the approximate thickness of the asphalt layer, and the density of the underlying material- in your case the gravel below.

From my experience, this method can give fair result, but I would check the results by comparing the results agains 3 cores in at least 3 places to make sure that the correction is working properly.

 

[woodleigh]

The nuclear gauges you discuss should only be used if you check them/calibrate them against actual cores (as ncarolinageo states), and often.

Seems lately, there are a lot of labs breaking into the asphalt business because their concrete and steel work slowed down due to economic reasons. Problem is that not all realize how temperamental gauges can be, and they are causing problems. For example, taking the values off an uncalibrated gauge and reporting 93% of rice density when cores cores end up reporting 88% (yes...this happened).

Don't just take that gauge out and assume it is going to give you accurate results without assuring yourself it's check every few days against actual cores.

 

[SirAl]

I would only apply nuclear density testing of ACP during construction to help obtain an optimum rolling/compaction pattern or, possibly to obtain a general idea of the compaction in much the same way that rebound hammer results would be applied as a qualitative measure of concrete compressive strength. There are too many potential variables to have confidence in the final numbers. In my opinion, you would have to correlate densities with core results. Cores are the only accepted method of determining field ACP compaction.

 

[lobeznofire]

hi !!
i dont know if someone here can help me but i would like to know which are the causes of a broken paviment because a i got a problem with that and i dont know how to fix.
somebody know if a page of cracks repaircan help me ?

 

[Ron]

lobeznofire....post your question in a new thread...don't scab onto an old one...you'll get more response.