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Handbook of Size Exclusion Chromatography and Related ...

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Figure 8 SEC LMS fraction vs. Fourier transform infrared spectroscopy carbonyl peak<br />

height for asphalts recovered from aged pavement cores (500/50 A ˚ , 60 cm PLgel, THF at<br />

1mL/min, 100 mL <strong>of</strong> 7 wt% solution, RI detector).<br />

growth in the carbonyl peak, an excellent measure <strong>of</strong> oxidation effects. The open<br />

circles in this figure include the data in Fig. 7<strong>and</strong> show asteady growth in the<br />

LMS region with carbonyl increase, but it is seen that with some asphalts, the<br />

growth in percentage LMS is small until higher levels <strong>of</strong> oxidation are reached.<br />

Severaltests, including SEC, were used to compare two st<strong>and</strong>ard oven-aging<br />

tests (the thin-film oven test, TFOT,ASTM D1754, <strong>and</strong> the rolling thin-film oven<br />

test, RTFOT,ASTM D2872) <strong>and</strong> to determine their accuracy in simulating the<br />

changes that occur in the hot-mix plant (33). The tests were also performed at<br />

extended times, <strong>and</strong> these data are designated ETFOT<strong>and</strong> ERTFOT.Asphalts <strong>and</strong><br />

hot-mixweretakenfromnineplantsusingsixdifferentsuppliers<strong>and</strong>withtwogrades<br />

fromonesupplier.Theasphaltswereagedintheoventests<strong>and</strong>comparedusingsix<br />

parameters. Figure 9shows the agreement in the percentage <strong>of</strong> LMS, <strong>and</strong> similar<br />

agreementwasobtainedfor the other parameters, confirmingthattheoventestsare<br />

interchangeable. The oven tests were then compared to asphalts from the extracted<br />

hot mixes. Figure 10 shows the disagreement between the oven tests <strong>and</strong> the<br />

recovered hot-mix asphalts, disagreements also confirmed by the other parameters.<br />

Thetestsweredesignedtoreproducethe608Cviscosity<strong>and</strong>dothisreasonablywell,<br />

© 2004 by Marcel Dekker, Inc.

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