What is the density to use between AC14 or 60/70 penetration grade???

[msesi]

I'm currently designing Asphalt concrete(AC14).The combination of the aggregate used are as follows:23%0f (10-14)mm,27% of (5-10)mm,48% of (0-5)mmm,3% 0f filler-crusher dust and 5% of 60/70 penetration grade bitumen.In the bill of quantity the bitumen 60/70 is to be paid in tonnes.The Contractor has used the density of the asphalt concrete AC14 instead of the 60/70 penetration grade.Which is the proper density to use between the two?????

 

[BigH]

At what temperature?

 

[Ron]

If I understand your question correctly, then you are asking about pay quantities of mix constituents. To determine the weight quantity of asphalt cement, you must know the mix density and the percent of asphalt cement in the mix...so

AC14 x 0.05= weight of Asphalt Cement per unit mix volume

Multiply by the total mix volume (say cubic meters or some other volumetric measurement) and you will get the weight quantity of the asphalt cement.

 

[TDAA]

As Ron says.

Also, in our practice, the tons of AC14 would be based off of the delivery tickets to the site, and the AC% would be based on the lab testing performed as part of the QA/QC testing, and not on the mix design quantity.

 

[msesi]

Hi Ron,thanks you for your replied.In principal in the bill of quantity the unit of AC14 is given in cum.And the AC14 comproposed of different aggregate size including 5%bitumen of 60/70penetration grade.The unit given in the bill of quantity for the bitumen is tonne.Now the Contractor wants to use AC14 density to convert the bitumen in tonnes instead of using the density of 60/70 penetration grade as the density of the AC14 is higher compared to the density of 60/70 penetration grade.

 

[Ron]

No. You are confusing two different quantities and characteristics. You only have two ways of determining the pay quantity of asphalt cement....you can use the printout of the mix design with the percent AC * the density of the AC14 mix * the total volume of the mix produced, or you can get a printout of metered quantity from the plant if they have the capability to measure and verify that way.

The density of an asphaltic concrete mix will be on the order of 2.1 to 2.3 times the density of water. The density of asphalt cement will be about the same density as water, maybe slightly less.