Short-term aging characterization of asphalt binders using gel permeation chromatography and selected Superpave binder tests

초록

Both the rolling thin film oven test (RTFOT) and the short-term oven aging (STOA) methods are used ill the laboratory to represent the aging of an asphalt binder during plant mixing, transportation and paving. The RTFOT is conducted at 163 degrees C for 85 min, and the recommended STOA methods are to heat the loose mix in a forced draft oven either at 135 degrees C for 4 h or at 154 degrees C for 2 h dependent on the asphalt binder's stiffness. The actual time of short-term aging ill the field varies depending oil hauling distances or paving times. This research was initiated to compare the aging effects of the RTFOT and the STOA methods using the gel permeation chromatography (GPC) and selected Superpave binder tests. For this study, nine asphalt binders were prepared, and five aging periods were used for the RTFOT and four aging treatments were selected for the STOA. Loose asphalt mixes were obtained from six field projects. The results of GPC test showed that the RTFOT method has less aging effect on the binders than the STOA methods for asphalt mixtures prepared in the laboratory. Given the limited number of samples from the field, it was difficult to find any correlation of short-term aging between the laboratory and the field. The longer the aging time ill the RTFOT led to an increase in the high temperature viscosity and the high failure temperature of asphalt binders, the only exception being the rubber-modified binders. The GPC was effective ill evaluating the aging effect of rubber-modified binders using different RTFOT aging times. (C) 2007 Elsevier Ltd. All rights reserved.

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