Department of Transportation
for Road and Bridge Construction
NJDOT B-5 – Determining Composition of Hma Mixture Using
Hot Bin Sample Analysis
- Scope. This test method is used to determine the gradation and asphalt content of a HMA mixture by use of bin samples and printout ticket.
- Apparatus. Use apparatus according to AASHTO T 11, T 27, and T 37.
- Procedure. Perform the following steps:
- When taking samples for hot bin analysis, apply the rates of sampling to the plant’s production for all Department projects rather than for individual projects.
- Divide the production into successive lots of the size as specified in Section 902 for the mixture being sampled. Take 5 samples for composition testing from each lot. Take 5 samples of the HMA as specified in NJDOT B-2 for volumetric acceptance testing, maximum specific gravity testing, and comparison testing from each lot. Time the HMA sampling to correspond with the hot bin samples.
- The ME will assign consecutive lot numbers for each type of mix at the plant. Include the assigned lot identification number on each weigh ticket.
- The ME will use a table of random numbers to select the ton of mix to be sampled for each sample in the lot. Based on the ton of mix, determine the portion of the production to be sampled.
- The supplier’s quality control technician shall take random samples of not less than 25 pounds from each hot bin for each 600 tons batched as directed by the ME. When mineral filler is used, take a minimum of one filler sample per lot.
- Use a minimum sample weight for testing of 25 pounds for bins No. 5 and No. 4, 10 pounds for bin No. 3, and 2 pounds for bin No. 2. Use a minimum test sample weight of 500 grams for bin No. 1 and 100 grams for mineral filler.
- For test samples from bins No. 2, 3, 4, and 5, weigh the sample and sieve the aggregate according to AASHTO T 27 down to the No. 8 sieve with a catch pan underneath. Conduct the sieving operation by means of a mechanical sieve shaker. If more than 2 percent of the aggregate is passing the No. 8 sieve, wash and grade that portion according to AASHTO T 11 and T 27.
- Wash and grade the bin No. 1 test sample according to AASHTO T 11 and T 27.
- For each bin, record the weight retained on each sieve determined in the grading process and the wash loss and pan weights for determination of the percent passing the No. 200 sieve.
- Wash and grade the mineral filler sample according to AASHTO T 37.
- Calculations. Calculate the asphalt content by dividing the recorded delivery ticket asphalt cement weight for the load by the total load weight.
Calculate the percent of material from each bin by dividing the recorded delivery ticket weights for each bin by the total aggregate weight of the load. Calculate the mix gradation by computing the percentage of material passing each sieve for each bin and multiplying the percentage by the individual bin percentage and then summing the products for each sieve.
- Report. Report the asphalt content to the nearest 0.01 percent on the work sheet and the daily inspection report and rounded to the nearest 0.05 percent when reported on the lot data report.
Report bin percentages, bin gradations, and the mix gradation to the nearest 0.1 percent on the work sheet and daily inspection report. On the lot data report, report the mix gradation to the nearest 0.5 percent on the No. 8 sieve, to the nearest 0.1 percent on the No. 200 sieve, and to the nearest 1 percent on all other sieves.
Last Document Correction:
December 14, 2007