Department of Transportation
for Road and Bridge Construction
NJDOT A-6 – Determining Gradation of Dense-Graded Aggregate
- Scope. This test method is used to rapidly determine the gradation of DGA containing more than 10 percent RAP. Due to the melting and adhering of the asphalt portion of RAP, typical oven or hotplate drying of the sample is detrimental. This test method is a modification of AASHTO T 27.
- Apparatus. Use apparatus according to AASHTO T 2, T 11, T 27, and M 92.
- Procedure. Perform the following steps:
- Sieve a minimum 5000-gram sample of DGA without drying (wet-sieved) through the following sieves: 2-inch 1-1/2-inch, 3/4-inch, and No. 4. Weigh the material retained on each sieve and the material passing the No. 4 sieve. Record the weights.
- Reduce the material passing the No. 4 sieve to a 500-gram sample.
- Spread the 500 gram sample out in a pan and put it in an oven preheated to 175 ± 5 °F for approximately 1.5 hours. At 15 minute intervals, remove the sample from the oven and weigh it. Remix the material to promote even and thorough drying then return it to the oven. Continue to dry the material until it reaches a constant weight.
- After drying the material passing the No. 4 sieve to a constant weight, record the final weight.
- Wash the material passing the No. 4 sieve according to AASHTO T 11 and dry the sample using the procedure in Step 3.
- Determine the gradation of the sample according to AASHTO T 27.
- Mathematically combine the gradation results of the plus No. 4 and minus No. 4 portions of the material for a final gradation.
- Report. Report the mathematically combined gradation results reported as a total percent passing the required sieves.
Last Document Correction:
December 14, 2007