New Jersey

Department of Transportation

Standard Specifications

for Road and Bridge Construction

2007


NJDOT B-9 – Determining Asphalt Content for MOGFC Courses
by Aggregate Surface Area

  1. Scope. This test method is used to determine the asphalt content to be used in MOGFC mixes based on the surface area of the aggregate. This percentage is averaged with asphalt contents determined according to NJDOT B-8 to arrive at a design asphalt content for a MOGFC mix design.

  2. Apparatus. Use the following apparatus:

    1. Ovens capable of maintaining temperatures of 140 ± 5 °F and 230 ± 9 °F.
    2. Balance meeting the requirements of AASHTO M 231, Class D.
    3. Two metal funnels having minimum dimensions of 3-1/2 inch top diameter, 4-1/2 inch high and 1/2 inch orifice. The funnels shall have a metal strainer soldered where the base of the cone connects to the top of the spout. The equivalent size of the strainer shall not be larger than No. 10 sieve.
    4. A 3/8-inch sieve and a No. 4 sieve according to AASHTO M 92.
    5. SAE No. 10 lubricating oil.
    6. Two rubber stoppers to fit the funnel outlets.
    7. Ring stand to support the funnels during testing.
    8. Equipment required in AASHTO T 85.

  3. Procedure. Perform the following steps:

    1. Determine the apparent specific gravity of the aggregate passing the 3/8-inch sieve and retained on the No. 4 sieve according to AASHTO T 85.
    2. Through quartering, obtain 2 samples weighing approximately 110 grams representative of the material passing the 3/8-inch sieve and retained on the No. 4 sieve.
    3. Dry the sample in the 230 °F oven to a constant weight and allow to cool to room temperature.
    4. Weigh out 100.0 grams of the material and place in the metal funnel.
    5. Place a stopper in the funnel outlet and fill funnel with SAE No. 10 oil, immersing the aggregate.
    6. After 5 minutes, remove the stopper and allow the oil to drain for 2 minutes.
    7. Place the funnel containing the aggregate on a pan in the oven maintained at 140 °F for 15 minutes of additional draining.
    8. Remove the sample from the funnel, cool to room temperature, reweigh to the nearest 0.1 gram, and record.

  4. Calculations. Perform the following calculations:

    1. Calculate the percent oil retained for each sample as follows:


      2.    R = 
      B − A 

      		 x 100
      A
      		  
      Where:
      R =  Percent oil retained
      A =  Weight of sample before test
      B =  Weight of sample after test

    2. Using the average percent oil retained of the 2 samples, calculate the corrected percent oil retained as follows:


      3.    Rc = R − 
      Ga 

      		 x 100
      2.65 
      		  
        Where:
      Rc =  Corrected percent oil retained
      Ga =  Apparent specific gravity of aggregate
      2.65 =  Constant

    3. Using the corrected percent oil retained, determine the surface constant (Kc) from Table B-9-1.
    4. Calculate the design asphalt content as follows:

      5.    Design Asphalt Content = 
       ( 2.0 Kc + 4.0 ) x 2.65 

      Ga


      Table B-9-1 – Determination of Surface Constant Kc
      CORR.
      % OIL      		 Kc CORR.
      % OIL      		 Kc CORR.
      % OIL      		 Kc CORR.
      % OIL      		 Kc
      0.1 0.1 2.6 1.2 5.1 2.2 7.6 3.1
      0.2 0.1 2.7 1.2 5.2 2.2 7.7 3.1
      0.3 0.2 2.8 1.2 5.3 2.2 7.8 3.2
      0.4 0.2 2.9 1.3 5.4 2.3 7.9 3.2
      0.5 0.3 3.0 1.3 5.5 2.3 8.0 3.2
      0.6 0.3 3.1 1.4 5.6 2.3 8.1 3.3
      0.7 0.4 3.2 1.4 5.7 2.4 8.2 3.3
      0.8 0.4 3.3 1.4 5.8 2.4 8.3 3.4
      0.9 0.4 3.4 1.5 5.9 2.5 8.4 3.4
      1.0 0.5 3.5 1.5 6.0 2.5 8.5 3.4
      1.1 0.5 3.6 1.6 6.1 2.5 8.6 3.5
      1.2 0.6 3.7 1.6 6.2 2.6 8.7 3.5
      1.3 0.6 3.8 1.6 6.3 2.6 8.8 3.5
      1.4 0.7 3.9 1.7 6.4 2.6 8.9 3.6
      1.5 0.7 4.0 1.7 6.5 2.7 9.0 3.6
      1.6 0.7 4.1 1.8 6.6 2.7 9.1 3.6
      1.7 0.8 4.2 1.8 6.7 2.8 9.2 3.7
      1.8 0.8 4.3 1.8 6.8 2.8 9.3 3.7
      1.9 0.9 4.4 1.9 6.9 2.8 9.4 3.8
      2.0 0.9 4.5 1.9 7.0 2.9 9.5 3.8
      2.1 1.0 4.6 2.0 7.1 2.9 9.6 3.8
      2.2 1.0 4.7 2.0 7.2 2.9 9.7 3.9
      2.3 1.0 4.8 2.0 7.3 3.0 9.8 3.9
      2.4 1.1 4.9 2.1 7.4 3.0 9.9 3.9
      2.5 1.1 5.0 2.1 7.5 3.1 10.0 4.0

  5. Report. Report all test results on ME provided forms.

Last Document Correction:
December 14, 2007