U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
| REPORT |
| This report is an archived publication and may contain dated technical, contact, and link information |
|
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| Publication Number: FHWA-HRT-14-086 Date: November 2014 |
Publication Number: FHWA-HRT-14-086 Date: November 2014 |
IATROSCAN® TEST METHOD FOR SARA ANALYSIS OF ASPHALT
The heavy metals (typically vanadium and nickel) present in the asphaltene portion of asphalt binders have a tendency to contaminate the silica coating on the chromatographic rods. For this reason, the asphaltenes are first separated by extracting the binder with n-heptane and removing the insoluble asphaltenes by filtration. The n-heptane soluble portion is then absorbed on 5-micron silica-gel coated glass rods (Chromarods®) and fractionated by upward elution using specific solvent types, development methods, and duration. The three separated fractions are then burned from the rods using flame ionized detection (FID). As the materials burn the ionic combustion products can be detected by a FID system. The FID system provides specific response to organic compounds; therefore, three chromatographic fractions are separated and identified as resins, cyclics, and saturates. These, together with asphaltenes, comprise the four generic fractions found in asphalt. The FID system provides specific response to compounds containing nitrogen and or halogens.
The following apparatus is used to conduct the test:
Asphaltene/Material Separation
Sample Preparation
During the asphaltene oven drying period, obtain the volume of filtrate by pouring it into a graduated cylinder. Note this volume because it will be needed to calculate the maltene concentration. Pour n-heptane filtrate into an amber glass bottle and place in a cool, dark area for 2 + 0.10 h.
During this period, asphaltenes analysis may be completed. After obtaining the asphaltene weight, calculate the maltene concentration as follows:
Maltene Concentration = (Sample Wt. - Asphaltene Wt.)/Volume n-Heptane Filtrate
Figure 70. Equation. Calculation of maltene concentration.
Report this concentration in micrograms per milliliter (µg mL-1).
Approximately 20µg of maltenes are needed on each Chromarod® for analysis. Therefore, the quantity of n-heptane filtrate in µL (microliters) may be calculated as follows:
Quantity (µg)=Qaulity Required (µg)/Concentration (µg mL-1) x (1000)
Figure 71. Equation. Calculation of n-heptane filtrate.
Report the value in microliters (µL) and round up to the nearest whole unit. This is the volume to be injected on each Chromarod®.
Solvent Preparation
Use two solvent tanks (1.5 by 7 inches) as solvent baths. Place clean filter paper on the inside of the back of the tank to enhance vapor transmission in the tank. Fill the first solvent tank with n-pentane (chromatographic grade) to a point just below the spotting point on the rack (approximately 1 inch). The next tank should be filled to the same level as the pentane tank with a 90/10 volume percent ratio toluene/chloroform (chromatographic grade) solvent mixture.
Spotting Chromarods®
To spot the sample on the Chromarods®, use a syringe capable of delivering 0.2 µL. Using SIII Chromarods®, spot the calculated quantity in applications of 0.2 µL, rotating the rod to cover the circumference of the rod to yield five even spots around the circumference of the rod.
Component Separation
After spotting the rods, allow 2 min in the desiccator at room temperature and 50 ± 5% relative humidity (RH) for drying. Place the rods in the n-pentane tank for 20 minutes allowing the solvents to migrate upwards to the 10 cm mark on the rod rack. This migration will elute the saturates portion of the maltene fraction to the 10 cm on the rod rack. When the solvent reaches the 10 cm mark, remove the rods from the tank and allow 10 min at room temperature and 50+ 5% RH for drying. After drying, place the rods in the 90/10 toluene/chloroform tank for 7 min, allowing the solvents to migrate upward to the 5 cm mark on the rod rack. This migration will elute the resins and cyclics portion of the maltene, where cyclics are moved by the blend of toluene and chloroform, and the resins remain on the rod slightly above the original spot. Remove the rod rack from the development tank and dry in a forced air oven at 90 °C for 15 min. Cool in desiccator for 10 min.
Place the rods in the Iatroscan® hydrocarbon analyzer and burn them with the hydrogen flame. The results are collected by the Iatroscan® software.
Iatroscan Settings used: Hydrogen Flow, 160 µL/min., Air Flow, 2.0 L/min. Scanning Speed: 30 s for each rod. The heptane solution contained 0.25 g of maltene in 25 mL, which required a 4.0 µL spot to be placed on the rods with the syringe.
Report the asphalt composition in percents of each component as follows:
Initial stiffness of acid-modified binders and after oven aging for 24 h at 165 °C are reported in table 12 through table 15.
Table 12 . Change in stiffness of asphalt AAD-1 with phosphoric acid modification immediately after mixing and after 24 h at 165 °C.
Acid Strength (percent) |
|G*|/Sinδ at 64 °C |
|||
|---|---|---|---|---|
115 |
0.89 |
1.25(1.38) |
1.77(1.83) |
4.23(4.47) |
105 |
0.89 |
1.07(1.57) |
1.44(2.20) |
2.87(3.74) |
85 |
0.89 |
1.45(1.57) |
2.04(2.49) |
3.89(3.90) |
75 |
0.89 |
1.51(1.91) |
2.04(2.38) |
3.43(3.69) |
50 |
0.89 |
1.68 |
2.71 |
5.6 |
Addition Level (percent) |
0 |
0.25 |
0.5 |
1.0 |
Table 13. Change in stiffness of asphalt AAM-1 with phosphoric acid modification immediately after mixing and after 24 h at 165 °C.
Acid Strength (percent) |
|G*|/Sinδ at 64 °C |
|||
|---|---|---|---|---|
115 |
1.69 |
1.98(2.09) |
2.89(2.80) |
6.14 (4.48) |
105 |
1.69 |
1.98(2.08) |
2.59(2.58) |
4.23(3.65) |
85 |
1.69 |
2.07(2.19) |
2.70(2.95) |
3.98(4.50) |
75 |
1.69 |
2.18(2.25) |
2.63(3.40) |
4.67(4.68) |
50 |
1.69 |
2.30 |
3.48 |
6.34 |
Addition Level (percent) |
0 |
0.25 |
0.5 |
1.0 |
Table 14. Change in stiffness of asphalt AAK-1 with phosphoric acid modification immediately after mixing and after 24 h at 165 °C.
Acid Strength (percent) |
|G*|/Sinδ at 64 °C |
|||
115 |
2.43 |
3.60(3.17) |
3.85(4.65) |
9.13(9.07) |
105 |
2.43 |
3.24(4.09) |
4.58(4.67) |
8.49(9.69) |
85 |
2.43 |
3.74(4.18) |
4.46(4.91) |
8.52(8.79) |
75 |
2.43 |
3.86(3.76) |
4.47(5.75) |
8.04(7.69) |
50 |
2.43 |
3.79 |
6.17 |
10.17 |
Addition Level (percent) |
0 |
0.25 |
0.5 |
1.0 |
Table 15 . Change in stiffness of asphalt ABM-1 with phosphoric acid modification immediately after mixing and after 24 hours at 165 °C.
Acid Strength (percent) |
|G*|/Sinδ at 64 °C |
|||
|---|---|---|---|---|
115 |
1.65 |
1.25(1.34) |
1.25(1.25) |
1.43(1.58) |
105 |
1.65 |
1.28(1.34) |
1.23(1.33) |
1.13(1.28) |
85 |
1.65 |
1.41(1.59) |
1.36(1.40) |
2.47(1.49) |
75 |
1.65 |
1.20(1.36) |
1.26(1.51) |
1.22 |
50 |
1.65 |
1.28 |
1.48 |
1.83 |
Addition Level (Percent) |
0 |
0.25 |
0.5 |
1.0 |
EFFECT OF OVEN AGING 12 DAYS AT 165 °C ON ASPHALT STIFFNESS
Table 16 . Oven aging at 165 °C asphalt AAD-1 modified with 115-percent phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
0.89 |
1.25 |
1.77 |
4.23 |
24 |
- |
1.38 |
1.83 |
4.47 |
48 |
- |
1.69 |
1.92 |
4.89 |
72 |
- |
2.39 |
2.77 |
6.62 |
96 |
- |
3.03 |
3.18 |
9.88 |
120 |
1.13 |
4.5 |
4.61 |
12.41 |
288 |
5.92 |
5.02 |
7.53 |
27.95 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 17. Oven aging at 165 °C asphalt AAD-1 modified with 105-percent phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
0.89 |
1.07 |
1.44 |
2.87 |
24 |
- |
1.57 |
2.2 |
3.74 |
48 |
- |
1.95 |
1.9 |
3.37 |
72 |
- |
2.99 |
2.84 |
4.34 |
96 |
- |
4.43 |
3.58 |
5.62 |
120 |
1.13 |
4.85 |
4.26 |
6.44 |
288 |
5.92 |
7.21 |
7.54 |
9.52 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 18. Oven aging at 165 °C asphalt AAD-1 modified with 85-percent phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
0.89 |
1.45 |
2.04 |
3.89 |
24 |
- |
1.57 |
2.49 |
3.9 |
120 |
1.13 |
1.58 |
2.88 |
- |
288 |
5.92 |
3.9 |
5.15 |
9.04 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 19. Oven aging at 165 °C asphalt AAD-1 modified with 75-percent phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
0.89 |
1.51 |
2.04 |
3.43 |
24 |
- |
1.91 |
2.38 |
3.69 |
120 |
1.13 |
2.61 |
3.36 |
4.49 |
288 |
5.92 |
4.66 |
5.46 |
6.67 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 20. Oven aging at 165 °C asphalt AAD-1 modified with 50-percent "green" phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
0.89 |
1.68 |
2.71 |
5.6 |
120 |
1.13 |
- |
- |
|
168 |
|
2.46 |
3.45 |
7.54 |
288 |
5.92 |
- |
- |
- |
336 |
|
3.65 |
4.7 |
10.53 |
Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 21. Oven aging at 165 °C asphalt AAK-1 modified with 115-percent phosphoric acid .
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
2.43 |
3.6 |
3.85 |
9.13 |
24 |
2.8 |
3.17 |
4.65 |
9.07 |
48 |
- |
4.34 |
6.28 |
12.7 |
72 |
- |
6.33 |
7.95 |
17.37 |
96 |
- |
8.09 |
12.04 |
22.39 |
120 |
10.5 |
10.53 |
17.11 |
33.2 |
288 |
12.9 |
19.24 |
24.98 |
39.96 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 22. Oven aging at 165 °C asphalt AAK-1 modified with 105-percent phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
2.43 |
3.24 |
4.58 |
8.49 |
24 |
2.8 |
4.09 |
4.67 |
9.69 |
48 |
- |
5.06 |
5.68 |
13.62 |
120 |
10.5 |
8.49 |
8.94 |
17.77 |
288 |
12.9 |
17.85 |
19.97 |
43.05 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 23. Oven aging at 165 °C asphalt AAK-1 modified with 85-percent phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
2.43 |
3.74 |
4.46 |
8.52 |
24 |
2.8 |
4.18 |
4.91 |
8.79 |
120 |
10.5 |
7.88 |
7.97 |
15.42 |
288 |
12.9 |
14.72 |
16.8 |
30.46 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 24. Oven aging at 165 °C asphalt AAK-1 modified with 75-percent phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
2.43 |
3.86 |
4.47 |
8.04 |
24 |
2.8 |
3.76 |
5.75 |
7.69 |
48 |
- |
5.37 |
7.85 |
11.82 |
120 |
10.5 |
16.69 |
22.25 |
23.79 |
288 |
12.9 |
33.38 |
33.02 |
45.31 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
Table 25. Oven aging at 165 °C asphalt AAK-1 modified with 50-percent "green" phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sin at 65 °C |
|||
|---|---|---|---|---|
0 |
2.43 |
3.79 |
6.17 |
10.17 |
24 |
2.8 |
- |
- |
- |
120 |
10.5 |
- |
- |
- |
168 |
|
6.03 |
6.65 |
17.01 |
288 |
12.9 |
- |
- |
- |
336 |
- |
10.6 |
11.62 |
22.94 |
Acid Addition Level (percent) |
0- |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 26. Oven aging at 165 °C asphalt AAM-1 modified with 115-percent phosphoric acid
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
1.69 |
1.98 |
2.89 |
6.14 |
24 |
- |
2.09 |
2.8 |
4.48 |
48 |
- |
2.81 |
3.5 |
6.93 |
72 |
- |
4.06 |
4.49 |
7.26 |
120 |
1.96 |
5.8 |
7.5 |
8.04 |
288 |
11.68 |
11.48 |
14.9 |
13.11 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 27 . Oven aging at 165 °C asphalt AAM-1 modified with 105-percent phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
1.69 |
1.98 |
2.59 |
4.23 |
24 |
- |
2.08 |
2.58 |
3.65 |
48 |
- |
2.61 |
3.44 |
4.1 |
72 |
- |
3.59 |
4.07 |
4.41 |
120 |
1.96 |
5.26 |
5.27 |
3.36 |
288 |
11.68 |
9.15 |
8.74 |
7.11 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 28 . Oven aging at 165 °C asphalt AAM-1 modified with 85-percent phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
1.69 |
2.07 |
2.7 |
3.98 |
24 |
- |
2.19 |
2.95 |
4.5 |
120 |
1.96 |
5.51 |
7.92 |
5.49 |
288 |
11.68 |
12.73 |
12.77 |
8.83 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 29. Oven aging at 165 °C asphalt AAM-1 modified with 75-percent phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
1.69 |
2.18 |
2.68 |
4.67 |
24 |
- |
2.25 |
3.4 |
4.68 |
120 |
1.96 |
2.32 |
10.17 |
6.49 |
288 |
11.7 |
12.11 |
14.52 |
13.37 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 30. Oven aging at 165 °C asphalt AAM-1 modified with 50-percent "green" phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
1.69 |
2.3 |
3.48 |
6.34 |
120 |
1.96 |
- |
- |
- |
168 |
|
7.92 |
8.75 |
7.47 |
288 |
11.68 |
- |
- |
- |
336 |
- |
15.66 |
15.11 |
9.84 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 31. Oven aging at 165 °C asphalt ABM-1 modified with 115-percent phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
1.65 |
1.25 |
1.25 |
1.43 |
24 |
- |
1.34 |
1.25 |
1.58 |
48 |
- |
1.53 |
1.37 |
1.62 |
72 |
- |
1.72 |
1.69 |
2.01 |
120 |
1.52 |
3.12 |
2.11 |
4.23 |
288 |
1.81 |
8.86 |
2.34 |
18.79 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 32. Oven aging at 165 °C asphalt ABM-1 modified with 105-percent phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
1.65 |
1.28 |
1.23 |
1.13 |
24 |
- |
1.34 |
1.33 |
1.28 |
48 |
- |
1.43 |
1.58 |
- |
120 |
1.52 |
1 |
1.85 |
1.37 |
288 |
1.81 |
1.72 |
2.68 |
3.36 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 33. Oven aging at 165 °C asphalt ABM-1 modified with 85-percent phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
1.65 |
1.41 |
1.36 |
2.47 |
24 |
- |
1.59 |
1.4 |
1.49 |
120 |
1.52 |
1.46 |
2.39 |
2.75 |
288 |
1.81 |
3.54 |
5.49 |
10.47 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 34. Oven aging at 165 °C asphalt ABM-1 modified with 75-percent phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
1.65 |
1.2 |
1.26 |
1.22 |
24 |
- |
1.36 |
1.51 |
- |
120 |
1.52 |
1.83 |
3.09 |
2.96 |
288 |
1.81 |
5.09 |
7.97 |
8.89 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
Table 35 . Oven aging at 165 °C asphalt ABM-1 modified with 50-percent "green" phosphoric acid.
Hours at 165 °C |
Stiffness |G*|/Sinδ at 65 °C |
|||
|---|---|---|---|---|
0 |
1.65 |
1.28 |
1.48 |
1.83 |
120 |
1.52 |
- |
- |
- |
168 |
|
4.14 |
6.28 |
6.98 |
288 |
1.81 |
- |
- |
- |
336 |
|
21.45 |
30.37 |
45.27 |
Acid Addition Level (percent) |
0 |
0.25 |
0.5 |
1 |
- Indicates not measured
DOES PHOSPHORIC ACID CAUSE OXIDATION IN ASPHALT BINDERS?
Table 36 . PAV aging asphalt ABM-1 under air pressure at 100 °C.
Hours |
Control |
105 percent |
115 percent |
P2O5 |
|---|---|---|---|---|
0 |
1.37 |
1.12 |
1.3 |
1.46 |
24 |
1.68 |
1.12 |
1.19 |
1.41 |
168 |
5.09 |
2.83 |
2.62 |
2.87 |
336 |
9.13 |
5.88 |
6.08 |
5.66 |
Table 37 . PAV aging asphalt AAD-1 under air pressure at 100 °C.
Hours |
Control |
105 percent |
115 percent |
P2O5 |
|---|---|---|---|---|
0 |
1.03 |
4.05 |
4.75 |
1.38 |
24 |
1.21 |
4.07 |
3.95 |
1.73 |
168 |
14.35 |
10.83 |
12.26 |
12.4 |
336 |
36.83 |
21.17 |
20.31 |
37.82 |
Table 38 . PAV aging asphalt AAK-1 under air pressure at 100 °C.
Hours |
Control |
105 percent |
115 percent |
P2O5 |
|---|---|---|---|---|
0 |
2.27 |
8.65 |
7.99 |
2.65 |
24 |
3.23 |
9.36 |
7.47 |
2.93 |
168 |
9.84 |
19.04 |
17.5 |
13.85 |
336 |
20.67 |
28.30 |
29.87 |
31.61 |
Table 39 . PAV aging asphalt AAM-1 under air pressure at 100 °C.
Hours |
Control |
105 percent |
115 percent |
P2O5 |
|---|---|---|---|---|
0 |
1.65 |
3.85 |
6.50 |
1.95 |
24 |
2.16 |
3.80 |
5.02 |
2.11 |
168 |
10.94 |
8.03 |
8.52 |
9.17 |
336 |
30.1 |
11.68 |
9.32 |
19.21 |
Table 40 . PAV aging asphalt ABM-1 under nitrogen pressure at 100 °C.
Hours |
Control |
50 percent |
85 percent |
115 percent |
|---|---|---|---|---|
0 |
0.73 |
|
|
|
24 |
|
|
|
|
168 |
|
7.35 |
4.18 |
3.67 |
336 |
1.17 |
9.37 |
5.3 |
4.41 |
Table 41. PAV aging asphalt AAD-1 under nitrogen pressure at 100 °C.
Hours |
Control |
50 percent |
85 percent |
115 percent |
|---|---|---|---|---|
0 |
0.73 |
|
|
|
24 |
|
|
|
|
168 |
|
7.35 |
4.16 |
3.67 |
336 |
1.17 |
9.37 |
5.3 |
4.41 |
- Indicates not measured
Table 42. PAV aging asphalt AAK-1 under nitrogen pressure at 100 °C.
Hours |
Control |
50 percent |
85 percent |
115 percent |
|---|---|---|---|---|
0 |
2.35 |
|
|
|
24 |
|
|
|
|
168 |
|
15.21 |
8.02 |
9.21 |
336 |
4.37 |
16.38 |
9.64 |
9.53 |
- Indicates not measured
Table 43 . PAV aging asphalt AAM-1 under nitrogen pressure at 100 °C.
Hours |
Control |
50 percent |
85 percent |
115 percent |
|---|---|---|---|---|
0 |
1.38 |
|
|
|
24 |
|
|
|
|
168 |
|
6.34 |
3.95 |
5.22 |
336 |
2.31 |
7.87 |
3.8 |
4.73 |
- Indicates not measured
