Bulk specific gravity of asphalt cores

[ehenke]

Hello,

I work for a small Geotech engineering firm and we are trying to determine the bulk specific gravity of some HMAC cores- using AASHTO T166. Our results failed the specs and we want to rerun because we basically rigged our own bucket on a scale using a sawhorse and have never done this before. My question- is this test possible to run twice because we are having a hard time getting the moisture back out of the cores.

Any advice is much appreciated. I suggested having a testing lab who is certified by AMRL run the tests but apparently that's not in the budget.

Thank you

 

[GeoEnvGuy]

If you say your doing aashto t166, with a rigged sawhorse, bucket and scale, who is going to certify the laboratory results to say they do or do not meet specifications? If sending the cores to a certified lab is not within your budget then it must not be in your scope.

To address your question of can you run the test twice, no you cannot as you are not certified to complete the aashto t166 test in the first place to determine if the material meets specifications.

 

[ehenke]

Thanks for your reply. Our specifier is not requiring an AASHTO/AMRL(former I know) certification on this test so sorry for the confusion. My question is if it is possible to rerun this test as the cores have water filling the air voids and I'm not sure the oven at ~130 degrees F will get the water out.

 

[GeoEnvGuy]

ASTM soils ovens run at 230F just above boiling point of water, unlikely 130F will remove water content to provide a dry sample for specific gravity determination.

 

[Ron]

Put the cores in a dessicator, not an oven. It might take a few days to reach equilibrium.

Keep in mind that the wire, the basket, the bucket and the water are not calibrated. The only device you have to be concerned about is the scale!

There is also a procedure that allows you to coat the cores with paraffin to prevent absorption.

 

[ehenke]

Yes, it's the temperature of the oven that is off. I do not understand why T166 says that the oven must be capable of maintain the standard 230 degrees F but in the oven method it says: dry overnight at 125 plus/minus 5 degress. This seems contradictory. Thanks for the responses- I really wanted to send this to another lab who is familiar with this test.