Determining Asphalt BINDER Content IN

HOT MIX ASPHALT (hMA) Mixtures by Calculation




The percent of binder in hot mix asphalt mixtures can be determined by calculation using test results from IM 350 and IM 369.




IM 350, Determining Maximum Specific Gravity of Hot Mix Asphalt (HMA) Mixtures


IM 369, Determining Specific Gravity of Asphalt Binder




A. Determine the Effective Specific Gravity of the Aggregate, Gse.



*Gb at 77F/77F (25C/25C)


Throughout the first day of production, obtain at least three (3) samples of HMA, which will represent that day's production. Determine the maximum specific gravities on each of these samples according to IM 350 and determine the average. The binder contents may be obtained by measurements from tank stick or flow meter. The specific gravity of the binder may be obtained from the certification document or by test using IM 369.



B. After Gse has been determined it is used throughout the project to calculate the binder content of the mixture. If any proportions are changed Gse must be redetermined.


Determine the Binder Content for a given set of proportions, Pb.




The calculated asphalt content is reported to three (3) significant figures.


Example Calculations




Pb = 5.75

Gb = 1.021

Gmm = 2.451







Gse = 2.680

Gb = 1.021

Gmm = 2.451