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OCR for page 37
37
1.4
y = 0.0424x + 0.1168
in Figure 22. Note that the y-axis (Jnr) scales of these graphs
R2 = 0.5459 are different. For all of the modified binders, the maximum Jnr
1.2
was less than 20 1/Pa. However, for the unmodified binders,
1 much of the data was above this level and, in one case (as
Mass Loss (%)
130 C
shown in Figure 22), exceeded 100 1/Pa. Further analysis of
0.8
150 C these results is provided in the next section.
0.6 170 C
190 C
0.4 Analysis of Binder Degradation
0.2 Four binder characteristics were examined for evidence of
binder degradation due to exposure to high temperatures:
0
0 5 10 15 20 25 30
· Changes in the true grade critical high temperature of the
Opacity (%)
binders;
Figure 20. Comparison of mass loss and opacity data. · Changes in the true grade critical low temperature of the
binders;
· Changes in the phase angle of the binders at their respec-
Results of Re-Graded Binders tive grade temperatures; and
Binder grading results for the original binder materials and · Changes in the MSCR non-recoverable creep compliance.
the residues from the SEP tests are shown in Table 14. True
grades for the samples are shown based on the critical low Table 16 shows the change in the critical high temperatures,
that is, the change in critical high temperature from the origi-
temperatures determined from the bending beam rheometer
nal, unaged binder to the re-graded binder after SEP condition-
(BBR) test and the direct tension test (DTT). Also shown are
ing at each temperature (i.e., SEP residue Tc - Original Tc). The
the phase angles for each binder at the high PG temperature.
data show that the critical high temperatures increased with
These results are discussed in a later section regarding analy-
higher SEP temperatures. Increases in high temperature grades
sis of binder degradation.
are considered beneficial to rutting resistance. This trend is
expected since exposure to high temperatures increases molec-
MSCR Tests ular size through oxidation and polymerization and therefore
stiffens the binders. The three binders with the greatest increase
Table 15 is a summary of the results from the MSCR tests.
in the critical high temperature were I, O, and H. The high tem-
The information shown in this table is the non-recoverable perature grade for the air-blown Binder I changed the most
creep compliance results that indicate the degree to which a with a two-grade increase. Those that changed the least were
binder recovers shear strains resulting from a range of stresses. unmodified Binder K and modified Binder C, with an increase
Binders that are modified with elastomeric polymers will typ- in critical high temperature of 4.6°C and 4.4°C, respectively.
ically exhibit a high degree of recovery or, inversely, have very Although there are differences among the binders in the mag-
low values of non-recoverable compliance. Following the nitude of change of the high temperature grade due to the SEP
AASHTO TP 70 protocol, binders are normally tested after conditioning, there is no evidence of binder degradation from
rolling-thin-film oven (RTFO) conditioning at the binder's this data.
high PG temperature. However, initial MSCR tests on RTFO- Table 17 shows the change in the critical low temperature for
aged samples after the SEP procedure showed that the RTFO the binders. For most binders, the critical low temperature
aging masked the effects of the SEP tests. Therefore, no after the SEP testing was based on the DTT. Overall, the low
RTFO conditioning was performed on the SEP-conditioned critical temperatures typically increased several degrees from
binders to better assess the effects of the SEP temperatures the original binders, but not enough to change the grade for
on the binders. For this study, the binders were tested after most binders. This indicates that pavements with these binders
four temperatures (58°C, 64°C, 70°C, and 76°C) in the SEP would be only slightly more likely to experience thermal crack-
test. MSCR tests were conducted on the original and SEP ing after exposure to the temperatures in the SEP test. Binders
conditioned binder samples. Results are reported as non- that had the greatest increase in critical low temperature were
recoverable creep compliance, Jnr, at two standard levels of I, J, N and O. Of these, J, N, and O barely had a one-grade
stress, 100 and 3200 Pa. change at the low temperature end; Binder I did not change
Example plots of the change in Jnr with increasing test low temperature grade. There was no general trend of increas-
temperature and SEP conditioning are shown in Figures 21 ing critical low temperature with higher temperatures, and
and 22. Results for a modified Binder, H, are shown in Fig- most modified binders increased slightly less than the
ure 21, and the results of an unmodified Binder, E, are shown unmodified binders. Therefore, there is no strong evidence of
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Table 14. Results of grading of binders before and after
SEP testing.
SEP Test Temperature, °C
Binder Test Original 130 150 170 190
Original DSR 85.4 91.7 89.6 92.1 95.6
Phase Angle @
82°C 65.8 64.1 65.2 65.8 62.4
RTFO DSR 65.8 64.1 65.2 65.8 62.4
PAV DSR 24.1 23.0 25.4 26.7 26.9
M
BBR Stiffness -26.4 -27.3 -26.1 -28.7 -27.7
BBR m-value -19.5 -17.7 -16.4 -17.3 -17.3
DTT -24.8 -17.7 -17.3 -19.6 -21.5
True Grade - BBR 85.4 -19.5 88.4 -17.7 89.6 -16.4 90.8 -17.3 92.2 -17.3
True Grade - DTT 85.4 -24.8 88.4 -17.7 89.6 -17.3 90.8 -19.6 92.2 -21.5
Original DSR 96.6 88.9 94.6 98.7 97.7
Phase Angle @
82°C 70.0 69.6 71.4 66.5 66.1
RTFO DSR 84.3 83.0 85.7 88.9 91.0
PAV DSR 15.0 25.7 23.2 20.2 24.3
N
BBR Stiffness -33.1 -23.5 -24.4 -30.0 -30.5
BBR m-value -25.5 -22.3 -24.1 -23.8 -27.0
DTT -27.8 -18.4 -20.3 -20.5 -20.8
True Grade - BBR 84.3 -25.5 83.0 -22.3 85.7 -24.1 88.9 -23.8 91.0 -19.5
True Grade - DTT 84.3 -27.8 83.0 -18.4 85.7 -20.3 88.9 -20.5 91.0 -20.8
Original DSR 82.5 89.9 90.6 90.4 89.9
Phase Angle @
76°C 67.1 64.0 63.3 61.8 63.1
RTFO DSR 85.5 94.3* 87.9 88.7 89.8
PAV DSR 20.3 22.5 22.2 18.6 20.9
G
BBR Stiffness -27.1 ° -27.2 -25.8 -28.1 -26.7
BBR m-value -24.2 -24.3 -23.4 -23.5 -22.3
DTT -25.6 -23.9 -22.3 -24.3 -21.2
True Grade - BBR 82.5 -24.2 89.9 -24.3 87.9 -23.4 88.7 -23.5 89.8 -22.3
True Grade - DTT 82.5 -25.6 89.9 -23.9 87.9 -22.3 88.7 -24.3 89.8 -21.2
Original DSR 78.7 81.5 85.9 86.3 88.4
Phase Angle @
76°C 72.3 70.2 68.4 67.7 66.7
RTFO DSR 78.3 82.3 79.7 75.3 88.0
PAV DSR 20.3 22.0 22.7 25.3 26.3
H
BBR Stiffness -27.9 -28.0 -26.9 -26.8 -27.3
BBR m-value -27.7 -28.0 -27.3 -26.0 -26.4
DTT -26.1 -23.7 -22.4 -21.0 -22.7
True Grade - BBR 78.3 -27.7 81.5 -28.0 79.7 -26.9 86.3 -26.0 88.0 -26.4
True Grade - DTT 78.3 -26.1 81.5 -23.7 79.7 -22.4 86.3 -21.0 88.0 -22.7
Original DSR 77.8 79.3 85.3 80.0 91.3
Phase Angle @
70°C 62.4 64.0 63.6 63.3 57.2
RTFO DSR 75.1 76.2 76.6 77.9 79.5
PAV DSR 6.7 6.7 9.0 7.0 12.6
C
BBR Stiffness -39.6 -39.0 -41.0 -42.7 -41.0
BBR m-value -38.9 -38.1 -38.1 -40.3 -38.1
DTT -34.9 -36.8 -36.1 -37.7 -28.2
True Grade - BBR 75.1 -38.9 76.2 -38.1 76.6 -38.1 77.9 -40.3 79.5 -38.1
True Grade - DTT 75.1 -34.9 76.2 -36.8 76.6 -36.1 77.9 -37.7 79.5 -28.2
Original DSR 71.8 77.3 76.5 81.9 84.6
Phase Angle @ 70°C 80.2 78.2 77.8 74.8 73.4
RTFO DSR 74.8 78.3 79.9 80.6 83.9
PAV DSR 17.5 20.1 18.9 22.1 22.6
I BBR Stiffness -34.8 -33.9 -39.0 -30.8 -35.9
BBR m-value -29.2 -28.3 -27.8 -28.0 -23.3
DTT -25.8 -27.0 -25.4 -23.8 -23.2
True Grade - BBR 71.8 -29.2 77.3 -28.3 76.5 -27.8 80.6 -28.0 83.9 -23.3
True Grade - DTT 71.8 -25.8 77.3 -27.0 76.5 -25.4 80.6 -23.8 83.9 -23.2
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Table 14. (Continued).
Original DSR 69.3 72.8 72.6 74.4 75.7
Phase Angle @
64°C 71.8 68.7 68.9 67.1 65.6
RTFO DSR 69.8 71.1 71.6 72.4 74.5
PAV DSR 10.4 10.9 10.9 11.1 12.4
B
BBR Stiffness -37.3 -37.8 -38.5 -38.5 -38.3
BBR m-value -37.9 -37.7 -36.5 -36.2 -36.6
DTT -34.1 -34.9 -35.1 -33.0 -34.1
True Grade - BBR 69.3 -37.3 71.1 -37.7 71.6 -36.5 72.4 -36.2 74.5 -36.6
True Grade - DTT 69.3 -34.1 71.1 -34.9 71.6 -35.1 72.4 -33.0 74.5 -34.1
Original DSR 68.4 71.6 72.4 74.3 73.6
Phase Angle @ 64°C 83.5 85.4 85.2 83.6 83.6
RTFO DSR 67.8 70.2 71.1 76.5 74.3
PAV DSR 30.5 31.5 25.4 26.0 33.1
F BBR Stiffness -24.9 -23.4 -24.0 -23.6 -23.9
BBR m-value -23.5 -22.8 -22.7 -25.0 -22.2
DTT -21.3 -18.7 -18.2 -15.9 -18.5
True Grade - BBR 67.8 -23.5 70.2 -22.8 71.1 -22.7 74.3 -14.1 73.6 -22.2
True Grade - DTT 67.8 -21.3 70.2 -18.7 71.1 -18.2 74.3 -15.9 73.6 -18.5
Original DSR 65.6 69.1 70.2 74.1 76.0
Phase Angle @ 64°C 79.2 83.5 82.9 80.3 78.8
RTFO DSR 68.2 70.5 71.0 73.6 77.7
PAV DSR 19.2 20.1 20.6 20.2 22.1
O BBR Stiffness -29.7 -27.9 -28.0 -27.7 -27.3
BBR m-value -30.1 -27.5 -27.5 -27.5 -26.8
DTT -30.2 -23.8 -23.6 -22.8 -22.0
True Grade - BBR 65.6 -29.7 69.1 -27.5 70.2 -27.5 73.6 -27.5 76.0 -26.8
True Grade - DTT 65.6 -30.2 69.1 -23.8 70.2 -23.6 73.6 -22.8 76.0 -22.0
Original DSR 66.1 68.9 69.8 70.8 71.3
Phase Angle @ 64°C 89.1 88.0 86.7 88.1 88.3
RTFO DSR 65.3 67.1 67.3 68.3 69.9
PAV DSR 32.4 32.1 32.2 32.3 33.7
K BBR Stiffness -13.0 -11.6 -13.8 -11.7 -11.0
BBR m-value -15.8 -15.8 -15.8 -15.0 -14.1
DTT -14.5 -9.0 -12.0 -10.9 -11.5
True Grade - BBR 65.3 -13.0 67.1 -11.6 67.3 -13.8 68.3 -11.7 69.9 -11.0
True Grade - DTT 65.3 -14.5 67.1 -9.0 67.3 -12.0 68.3 -10.9 69.9 -11.5
Original DSR 64.3 69.1 71.6 72.0 74.8
Phase Angle @ 64°C 89.4 86.9 88.4 88.2 86.6
RTFO DSR 64.7 69.2 69.4 71.2 72.4
PAV DSR 27.0 31.1 27.9 29.1 30.0
J BBR Stiffness -21.2 -19.0 -23.9 -22.2 -29.8
BBR m-value -20.7 -19.7 -21.2 -20.5 -19.5
DTT -21.0 -14.3 -14.5 -13.6 -13.4
True Grade - BBR 64.3 -20.7 69.1 -19.0 69.4 -21.2 71.2 -20.5 72.4 -19.5
True Grade - DTT 64.3 -21.0 69.1 -14.3 69.4 -14.5 71.2 -13.6 72.4 -13.4
Original DSR 63.2 62.8 63.4 66.0 69.5
Phase Angle @ 58°C 83.0 82.7 82.4 81.1 78.6
RTFO DSR 60.9 63.9 65.6 65.9 71.3
PAV DSR 13.2 13.0 12.7 14.9 14.3
E BBR Stiffness -36.7 -35.2 -35.1 -34.8 -35.0
BBR m-value -33.1 -35.2 -32.5 -34.4 -31.2
DTT -34.7 -30.6 -29.4 -30.0 -29.2
True Grade - BBR 60.9 -33.1 62.8 -32.5 63.4 -32.5 65.9 -34.4 69.5 -31.2
True Grade - DTT 60.9 -34.7 62.8 -30.6 63.4 -29.4 65.9 -30.0 69.5 -29.2
Original DSR 60.3 62.4 64.8 65.2 67.6
Phase Angle @ 58°C 86.7 85.5 84.3 84.0 83.1
RTFO DSR 61.5 62.7 63.2 64.7 65.9
PAV DSR 15.5 15.2 14.8 15.1 15.1
D BBR Stiffness -31.7 -32.3 -31.8 -32.4 -31.1
BBR m-value -32.5 -33.1 -29.6 -31.9 -32.7
DTT -26.0 -29.2 -29.4 -29.0 -28.7
True Grade - BBR 60.3 -31.7 62.4 -32.3 63.2 -29.6 64.7 -31.9 65.9 -31.1
True Grade - DTT 60.3 -26.0 62.4 -29.2 63.2 -29.4 64.7 -29.0 65.9 -28.7
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Table 15. Summary of non-recoverable creep compliance (Jnr, 1/Pa) results from the MSCR tests.
Binder Temp, 100 Pa Stress 3200 Pa Stress
o
ID C Unaged 130 150 170 190 Unaged 130 150 170 190
58 0.0500 0.0474 0.3260 0.1727 0.0801 0.1000 0.1385 0.1326 0.1034 0.0685
64 0.0790 0.0906 0.1581 0.3835 0.0677 0.3200 0.2146 0.4109 0.3815 0.1955
M
70 0.1200 0.2653 0.5203 0.7644 0.4954 1.1600 0.9883 1.2364 1.0724 0.7160
76 0.1900 1.2122 2.9427 1.8101 0.8002 4.3400 3.5709 3.7888 3.2963 2.2566
58 0.0700 0.1168 0.0626 0.0898 0.0830 0.1000 0.1721 0.1075 0.0752 0.0650
64 0.1400 0.2719 0.1100 0.2053 0.4125 0.2600 0.4889 0.2553 0.2035 0.2313
N
70 0.3200 1.6612 0.4064 0.1997 1.8000 0.8100 3.2819 0.5446 0.4046 0.9200
76 0.6400 1.3371 0.1698 1.2114 3.8847 2.5100 4.2000 3.4903 1.0648 2.3238
58 0.1212 0.6695 0.9805 0.1026 0.0795 0.1380 0.1643 0.2130 0.0738 0.0892
64 0.2216 0.2820 0.4007 0.2440 0.0710 0.2766 0.2127 0.3105 0.2366 0.1446
G
70 0.3761 0.4049 0.6539 0.5106 0.5207 0.5261 0.5818 0.7040 0.4514 0.4505
76 0.6632 1.5013 0.9277 0.7518 0.6698 1.3357 1.2024 1.8758 1.3503 0.9594
58 0.4600 0.6478 0.4793 0.2325 0.2693 0.5900 0.3988 0.2392 0.2360 0.2935
64 1.0500 1.0481 1.0372 0.5652 0.8394 1.5800 0.8867 0.7175 0.6685 0.5154
H
70 2.6800 0.6555 2.2746 1.5635 0.7825 4.5700 2.2220 1.7273 2.0313 1.1710
76 5.7200 3.8550 4.2959 3.4807 2.0714 10.4800 5.4825 5.1347 5.2013 3.2522
58 1.0137 0.9253 0.3740 0.2232 0.2759 1.0075 0.5853 0.3754 0.3605 0.2803
64 0.3326 1.2603 0.7737 0.9677 0.4490 1.7533 1.3344 1.1739 1.8443 0.7928
C
70 0.3690 2.8768 2.1784 2.2559 1.8240 5.5538 4.8275 3.5356 3.9806 2.5025
76 5.4942 7.1843 4.3437 4.5098 2.7163 13.2738 12.5172 7.7141 11.6331 7.5678
58 2.4612 1.2553 1.0379 0.5284 0.0386 2.8189 1.0503 1.2532 0.7221 0.4895
64 3.6981 2.2093 1.6739 0.9204 0.1364 5.8972 2.9856 2.5595 1.6446 1.4043
I
70 14.5110 4.8845 4.4979 2.8155 1.7774 15.4491 7.3369 7.4084 4.8200 2.9999
76 17.6200 11.6020 6.4407 1.7802 9.4055 27.6559 16.3003 14.7119 8.3325 10.0338
58 1.1572 1.4219 0.2614 0.7081 0.6351 2.3519 0.9589 0.7046 0.7697 0.7519
64 2.5669 0.3968 0.9438 1.2274 1.5359 6.6602 2.7654 2.6778 1.8109 2.3599
B
70 6.4338 1.5680 2.0909 3.5332 3.8034 16.4549 6.7619 5.0541 5.5288 6.5341
76 18.4670 3.5533 6.7418 5.7535 0.3094 34.8406 12.4888 11.9631 10.7913 11.4966
58 2.9939 1.1228 2.2369 1.5380 2.1366 3.5428 2.7608 2.7867 2.5458 2.5664
64 7.1896 6.1727 5.6663 3.7491 4.5189 8.6328 7.5444 6.9656 6.0781 5.8350
F
70 15.5393 13.3200 12.2410 9.0157 10.6770 18.7640 16.4963 15.0584 12.9425 13.4653
76 32.0430 27.0610 24.8970 23.0810 23.8840 38.9281 33.0313 30.3894 30.4113 27.9788
58 6.0360 3.5217 2.8005 1.1717 0.4555 5.6938 4.5128 3.6350 2.3061 1.9970
64 10.3100 7.2912 2.4976 2.9879 2.0882 12.2366 10.3097 7.4744 5.7025 4.6595
O
70 21.7490 14.6570 12.8270 8.1640 2.7960 28.1559 22.5944 17.2275 13.2616 11.6398
76 27.2230 27.5810 24.8370 18.0570 8.1853 40.2125 41.9750 32.6094 25.0438 19.3758
58 4.8934 3.6084 1.8297 0.4587 1.6453 5.7784 4.4663 4.2838 3.3775 2.6775
64 10.9300 5.4157 4.8001 6.5832 3.4524 12.1772 9.5750 9.9984 9.2616 6.8888
K
70 22.3350 17.0770 16.5430 15.0000 13.2470 32.8875 24.7503 24.4169 21.0691 17.9931
76 35.2620 41.5150 34.8630 13.1870 14.8320 59.6625 53.2031 53.8750 38.6406 35.0313
58 5.4921 3.5265 2.7391 2.4878 0.7402 6.2943 4.5581 4.0203 3.3891 3.2017
64 13.8943 7.1120 6.4143 4.6326 0.6629 16.1071 10.9047 7.8103 7.3150 7.2913
J
70 29.3687 19.7640 11.8350 10.7630 9.2671 34.1458 26.0844 19.8675 16.7050 14.5859
76 58.7047 39.6080 12.1270 25.2900 16.7150 67.6948 51.0125 40.7594 36.2156 35.7234
58 11.3737 7.9921 3.0642 4.3426 2.2957 14.3829 10.7188 7.8388 8.2328 3.9384
64 23.5373 16.9930 13.4830 6.4829 4.7986 29.4433 22.8119 18.1700 15.7816 8.7728
E
70 46.0083 21.6180 22.2620 16.4600 9.0460 57.6240 47.0094 39.0000 27.7828 19.0259
76 92.1573 79.8670 64.1290 38.6380 28.6420 114.3906 92.6563 75.8344 56.0125 39.7531
58 10.1716 3.7658 6.0801 4.0700 4.9074 12.1819 8.7575 8.5525 7.0372 6.3491
64 22.0473 14.0720 10.7090 11.4250 9.5916 26.5592 19.2153 18.1231 12.6216 14.0603
D
70 44.5693 32.5280 23.3700 12.6540 17.1720 53.3438 41.9750 40.8813 30.4881 26.8969
76 83.0037 34.6660 48.3080 47.1410 40.3310 99.6958 45.4875 74.5125 63.8688 56.8281
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Binder H, 3200 Pa Stress
20
18
Unaged
16
SEP 130
14
SEP 150
12 SEP 170
Jnr (1/Pa)
SEP 190
10
8
6
4
2
0
52 58 64 70 76 82
Temperature (C)
Figure 21. Plot of Jnr for modified Binder H from MSCR tests.
Binder E, 3200 Pa Stress
100
Unaged
90
SEP 130
80 SEP 150
SEP 170
70
SEP 190
60
Jnr (1/Pa)
50
40
30
20
10
0
52 58 64 70 76 82
Temperature (C)
Figure 22. Plot of Jnr for unmodified Binder E from MSCR tests.
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Table 16. Changes to high temperature grade (°C) Table 18. Changes to Phase Angle (degrees)
after SEP test. after SEP tests.
SEP Temperature (°C) SEP Temperature (°C)
Binder ID True Binder ID True
Grade 130 150 170 190 Grade 130 150 170 190
M 85.5 -19.5 3.0 4.2 5.4 6.8 M 85.5 -19.5 -1.73 -0.62 0.05 -3.34
N 84.3 -25.5 -1.3 1.4 4.6 6.7 N 84.3 -25.5 -0.40 1.40 -3.50 -3.90
G 82.5 -24.2 7.4 5.4 6.2 7.3 G 82.5 -24.2 -3.07 -3.76 -5.32 -4.02
H 78.3 -26.1 3.2 1.4 8.0 9.7 H 78.3 -26.1 -2.10 -3.83 -4.57 -5.54
C 75.1 -38.7 1.1 1.5 2.8 4.4 C 75.1 -38.7 1.66 1.18 0.97 -5.21
I 71.8 -29.2 5.5 4.7 8.8 12.1 I 71.8 -29.2 -2.03 -2.44 -5.43 -6.80
B 69.3 -37.3 1.8 2.3 3.1 5.2 B 69.3 -37.3 -3.18 -2.93 -4.73 -6.22
F 67.8 -21.3 2.4 3.3 6.5 5.8 F 67.8 -21.3 1.89 1.70 0.12 0.13
O 65.6 -29.7 3.5 4.6 8.0 10.4 O 65.6 -29.7 4.29 3.67 1.06 -0.42
K 65.3 -13.0 1.8 2.0 3.0 4.6 K 65.3 -13.0 -1.06 -2.40 -1.03 -0.84
J 64.3 -20.7 4.8 5.1 6.9 8.1 J 64.3 -20.7 -2.50 -1.00 -1.20 -2.80
E 60.9 -33.1 1.9 2.5 5.0 8.6 E 60.9 -33.1 -0.31 -0.58 -1.96 -4.45
D 60.3 -31.7 2.1 2.9 4.4 5.6 D 60.3 -31.7 -1.23 -2.35 -2.68 -3.57
Avg. of Modified Binders 2.5 2.7 5.0 6.7 Avg. of Modified Binders -1.5 -1.4 -2.9 -4.7
Avg. of Unmodified Binders 3.1 3.6 6.1 7.9 Avg. of Unmodified Binders -0.1 -0.5 -1.6 -2.7
low temperature degradation due to exposure to higher tem- observed by Airey and Brown (28), had the polymers in the
peratures for most binders. modified binders been damaged by the increased tempera-
Table 18 shows the change in phase angle as measured in PG tures, the phase angles should have increased, indicating a loss
grading of the binders. These data show that generally, phase of elastic behavior. Therefore, the phase angle data indicates
angles tend to decrease with increasing SEP temperatures that there are no signs of polymer degradation in the binders.
for both modified and unmodified binders. However, a few Figure 23 shows the effect of SEP temperature on non-
binders had unusual results. Binders C, F, and O exhibited an recoverable creep compliance, Jnr, for the unmodified binders.
initial increase in phase angle at an SEP temperature of 130°C, The data shown in this graph are from the binder high grade
then decreased with higher SEP temperatures. A decrease in temperatures and a stress level of 3200 Pa. The trend evident
phase angle indicates that the binders became stiffer and more from this chart is that the non-recoverable compliance val-
elastic after they were exposed to higher temperatures. As ues decrease with higher SEP temperatures. Conversely, the
Table 17. Changes to low temperature grade (°C)
after SEP test.
18
SEP Temperature (°C)
Binder ID True
130 150 170 190 16
Grade
M 85.5 -19.5 1.8 3.1 2.2 2.2 14
N 84.3 -25.5 7.1 5.2 5.0 6.0 12
G 82.5 -24.2 0.3 1.9 0.7 3.0 10
H 78.3 -26.1 2.4 3.7 5.1 3.4 Jnr (1/Pa)
8
C 75.1 -38.7 2.1 2.8 1.2 0.8
6
I 71.8 -29.2 2.2 3.8 5.4 6.0
4
B 69.3 -37.3 -0.4 0.8 1.1 0.7
2
F 67.8 -21.3 2.6 3.1 5.4 2.8
J 0
O 65.6 -29.7 5.9 6.1 6.9 7.7 K
K 65.3 -13.0 5.5 2.5 3.6 3.0 D
F 0
J 64.3 -20.7 6.7 6.5 7.4 7.6 Binder ID 130
E 150
E 60.9 -33.1 2.5 3.7 3.1 3.9 I 170
D 60.3 -31.7 2.5 2.3 2.7 3.0 O 190 SEP Temp. (C)
Avg. of Modified Binders 2.9 2.2 2.7 2.6 Figure 23. MSCR Jnr results at 3200 Pa stress for
Avg. of Unmodified Binders 4.0 4.0 4.9 4.9 unmodified binders.
