HOT MIX ASPHALT GYRATORY SAMPLES 31 AND 32
[Closing Date: August 4, 2011]
Specimen Preparation / Batching Instructions:
Prepare four individual batches according to the proportions given in the table below, two batches for Sample 31 and two batches for Sample 32. Note that the
“butter batch” for each sample number is smaller than the “compaction batch”.
The sample materials were shipped in two boxes. Box one contains one bag of material retained on the No. 8 sieve and two separate bags of Fine Aggregate material passing the No. 8 sieve, one bag for Sample 31 and one bag for Sample 32. The two bags of Fine Aggregate contain identical material. Box two contains two cans of asphalt binder, one for Sample 31 and one for
Sample 32 and a single bag of each of the other aggregate size fractions (1/2-inch, 3/8-inch and #4). Use the first batch of each set to butter the mixing bowl. After removing the butter batch from the bowl, condition the butter batch, then split or quarter the butter batch to obtain the specimen for the maximum specific gravity test (1500 g minimum specimen size required). Compact the second batch from each set using the gyratory compactor. After compaction, determine the bulk specific gravity of each of the extruded specimens.
For this round of testing, no mineral filler is required because there is a sufficient amount of dust in the Fine Aggregate fraction
[passing 2.36 mm (No. 8)]. However, it is very important to obtain representative samples of the fine aggregate when batching the specimens. The fine aggregate is provided in a moist condition to prevent segregation.
To help prevent segregation and loss of fines during batching, use the quartering method or the miniature stockpile method of sampling (AASHTO T248 / ASTM
C702, Method B or C) to divide the Fine Aggregate in its moist condition into portions approximately equal to the weights needed for the batches. (The BUTTER batch is 0.8 times as large as the COMPACTION batch. The water content of the Fine
Aggregate was approximately 6.5% when packaged.) Then oven dry the Fine Aggregate portions and adjust the weights of the portions to the exact weights needed for the batches. Of course, the Coarse Aggregate should also be oven dried before batching the specimens.
Prepare all four batches by combining the materials provided in the manner described in the table below. Dry all material at a temperature of 110 o C (230 o F) before weighing. Make all necessary weighings to the nearest 0.1 gram if possible.
Sample No. 31 (1 batch) Sample No. 32 (1 batch)
1. 12.5 mm (1/2 in.)
2. 9.5 mm (3/8 in.)
3. 4.75 mm (No. 4)
4. 2.36 mm (No. 8)
5. Fine Aggregate
6. Mineral Filler
7. Asphalt Binder
Individual Mass
188.5
330.0
1272.7
1037.0
1099.9
0.0
167.9
Cumulative Mass
188.5
518.5
1791.2
2828.2
3928.1
3928.1
4096.0
Individual Mass
230.6
461.2
691.9
1441.4
1098.6
0.0
176.3
Cumulative Mass
230.6
691.8
1383.7
2825.1
3923.7
3923.7
4100.0
Sample No. 31 (1 batch) Sample No. 32 (1 batch)
1. 12.5 mm (1/2 in.)
2. 9.5 mm (3/8 in.)
3. 4.75 mm (No. 4)
4. 2.36 mm (No. 8)
5. Fine Aggregate
6. Mineral Filler
7. Asphalt Binder
Individual Mass
235.7
412.4
1590.9
1296.3
1374.8
0.0
209.9
Cumulative Mass
235.7
648.1
2239.0
3535.3
4910.1
4910.1
5120.0
Individual Mass
288.3
576.5
864.8
1801.7
1373.3
0.0
220.4
Cumulative Mass
288.3
864.8
1729.6
3531.3
4904.6
4904.6
5125.0
(Instructions Continued on the Next Page)

Instructions for Mixing / Conditioning / Compaction:
Follow the standard mixing, conditioning and compacting procedures specified in AASHTO T312-09 and R30-02 or ASTM
D6925-09. Be sure to condition all four batches (in accordance with R30-02 for Volumetric Mixture Design or ASTM D6925-09) for 2 h ± 5 minutes at the compaction temperature, stirring after 60 ± 5 minutes to maintain uniform conditioning. Please condition the butter batch before splitting or quartering the batch to obtain the specimen for maximum specific gravity testing. Do not compact the butter batch. Use the following mixing and compacting temperatures:
Mixing Temp: 154 to 160
°C (309 to 320°F)
; Compacting Temp: 144 to 147
°C (291 to 297°F)
Direction for Individual Tests: (If the Bulk Specific Gravity is determined using both the Saturated Surface –Dry Method and the
Vacuum Sealing Method, perform the Vacuum Sealing Method first in order to have dry specimens to begin the Saturated
Surface-Dry Method. If the plastic bag is punctured during testing, mark the appropriate box on the data sheet and be sure to follow the procedure provided in the test method for specimens that may contain moisture. The procedures for specimens containing moisture are different for AASHTO Test Methods T331 and T166 and ASTM Test Methods D6752 and D2726, so please be sure to mark which test methods were used. )
Maximum Specific Gravity of Bituminous Paving Mixtures AASHTO T209-10 or ASTM D2041-03:
After removing the butter batch from the mixing bowl, split or quarter the uncompacted butter batch to obtain the specimen (1500 g minimum specimen size required) for the maximum specific gravity test. (For this round of testing, it is intended for the specimens for maximum specific gravity to have been conditioned the same as the specimens to be compacted.) Use either the bowl or flask method. Report the maximum specific gravity to the nearest 0.001. Do not use the Supplemental Procedure for
Mixtures Containing Porous Aggregate.
Bulk Specific Gravity Saturated Surface-Dry Method AASHTO T166-10 or ASTM D2726-10:
Report the bulk specific gravity (not density) of the extruded specimen to the nearest 0.001.
Bulk Specific Gravity Vacuum Sealing Method AASHTO T331-10 or ASTM D6752-09:
Report the bulk specific gravity (not density) of the extruded specimen to the nearest 0.001.
Determine the Relative Density of Hot Mix Asphalt Specimens by Means of the Superpave Gyratory Compactor AASHTO T312-
09 or ASTM D6925-09: Compact the specimens using 100 gyrations. Report the height of the specimens at 8 gyrations (N ini
) and 100 gyrations (N des
) to the nearest 0.1 mm. Calculate and report the percent of maximum specific gravity (i.e. Relative
Density, % G mm
) at 8 gyrations (N ini
) and 100 gyrations (N des
) to the nearest 0.1 percent.