Asphalt Binders Blended with a High Percentage of Biobinders: Aging Mechanism Using FTIR and Rheology

Document Type

Article

Publication Date

7-30-2014

Department

Department of Civil, Environmental, and Geospatial Engineering

Abstract

The objective of this study is to characterize the rheological properties and aging mechanism of asphalt binders blended with high percentages of biobinders using Fourier transform infrared spectroscopy (FTIR). The petroleum asphalt was partially replaced by the biobinders at fractions of 30 and 70% by weight. Rotational viscometer (RV) and dynamic shear rheometer (DSR) tests were conducted for the rheological properties, and the rolling thin film oven (RTFO) test was conducted for the aging simulation. Loss of volatiles was obtained from the RTFO test, whereas the oxidation characterization was investigated through the FTIR test. The rheology results showed that the bioblended asphalt binder exhibit different rheological properties as compared with the control asphalt binder before and after the RTFO-aging. The mass loss test showed that the loss of volatiles of biobinders were much higher than the control asphalt binder. FTIR spectra analysis showed that additional C═C" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">C═CC═C, C─O" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">C–OC─O, C═O" role="presentation" style="box-sizing: border-box; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; position: relative;">C═OC═O and OH bonds were generated during the aging. Further chemical analysis revealed that the aging of biobinder originates from three aspects: the loss of volatiles, the dehydrogenation which formulates higher molecular weight compounds such as asphaltene, and the oxidation which resulted in chemicals such as acids, alcohol, and ester.

Publication Title

Journal of Materials in Civil Engineering

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