Fourier Transform Infrared Spectroscopy characterization of aging-related properties of original and nano-modified asphalt binders

The objective of this study is to analyze the effect of aging on asphalt binders under the conditions of dry and sufficient oxygen, and to identify the functional groups related to the fatigue and rutting of asphalt mixtures. During the asphalt aging process, the six functional groups (carboxylic acids, aldehydes, amides, anhydrides, esters and ketones) containing the carbonyl group can be found in the asphalt binders based on the Fourier Transform Infrared Spectroscopy (FTIR) test results and references. The functional groups containing the carbonyl group in the asphalt binders can be also used to correlate to the oxidation extent of asphalt binders. Three nanomaterials were added into the control asphalt binder to study the effect of aging. The three materials included polymer modified nanoclay (PMN), nonmodified nanoclay (NMN) and nanosilica (NS). The rolling thin film oven (RTFO) and pressure aging vessel (PAV) aging effects of the asphalt binders were analyzed to understand the functional polar groups in the asphalt system under short- and long-term aging conditions, respectively. The different asphalt binders were tested by FTIR to obtain the spectra of chemical groups. The FUR characterization results indicate that the carboxylic acids and ketones are the main aging components in the asphalt when exposed to air and oxygen. The esters and aldehydes in the asphalt are kept to a limited amount. Furthermore, these functional groups, along with the carbonyl group are closely related to the susceptibility of rutting and the fatiguing of asphalt mixtures. (C) 2015 Elsevier Ltd. All rights reserved.