The bitumen microstructure: a fluorescent approach

Handle, Florian; Füssl, Josef; Neudl, Susanna; Großegger, Daniel; Eberhardsteiner, Lukas; Hofko, Bernhard; Hospodka, Markus; Blab, Ronald; Grothe, Hinrich

doi:10.1617/s11527-014-0484-3

Cited by 95 publications

(52 citation statements)

References 50 publications

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“…An increasing number of studies related to this question have been observed in recent years (Allen, Little, Bhasin, & Glover, 2014; Eberhardsteiner et al, 2015b;Handle et al, 2016;Poulikakos et al, 2014). This may be related to the fact that advances in microscopy and spectroscopic techniques allow for a more detailed observation of complex organic materials like bitumen.…”

Section: Road Materials and Pavement Designmentioning

confidence: 99%

Effect of short-term ageing temperature on bitumen properties

Hofko

Falchetto

Grenfell

et al. 2017

Road Materials and Pavement Design

102

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Properties of asphalt mixtures after ageing are fundamental parameters in determining longterm performance (e.g. durability) of these materials. With increasing popularity of reduced temperature mixtures, such as warm-mix asphalt, WMA, the question remains how a reduction in short-term ageing affects the properties after long-term ageing of bituminous materials. This paper aims to improve our understanding of the effect of asphalt manufacturing temperature on ageing and the resulting mechanical properties of bituminous binder by studying the effect of short-and long-term ageing of different bitumen samples as a function of short-term ageing temperatures. For this purpose, round robin experiments were conducted within the RILEM technical committee (TC) 252 chemo-mechanical characterisation of bituminous materials by 10 laboratories from 5 countries using four binders of the same grade (70/100 pen) from different crude sources. The short-term ageing was carried out using the standard procedure for rolling thin film oven test (RTFOT), but varying the temperatures. Long-term ageing was carried out using the standard procedure for pressure aging vessel (PAV) in addition to RTFOT. For the mechanical characterisation, rheological data were determined by using the dynamic shear rheometer (DSR) and conventional tests, with needle penetration and softening point using the ring and ball method. The results show that although different short-term ageing temperatures showed a significant difference in the mechanical properties of the binders, these differences vanished after long-term ageing with PAV.Keywords: bitumen; DSR; long-term ageing; short-term ageing; asphalt; RTFOT; PAV IntroductionAs an organic material, bitumen undergoes changes in its mechanical characteristics, chemical composition and microstructure due to environmental effects over its lifetime (Glotova, Gorshkov, Kats, Shapiro, & Yureva, 1980;Lee, Tia, Ruth, & Page, 1997;Mills-Beale et al., 2012;Yao, Dai, & You, 2015). Loss of volatile components at elevated temperatures and oxidation are two main factors for these changes. In terms of mechanical properties, bitumen tends to become stiffer, more elastic and brittle over time. Road Materials and Pavement Design109 SARA (saturates, aromatics, resins and asphaltenes) fractions can be observed with an increasing amount of asphaltenes and decreasing amount of aromatics over time Lu & Isacsson, 2002). These changes are generally summarised under the term "ageing". Bitumen ageing can be split up into short-term and long-term ageing. In the case of hot mix asphalt, short-term ageing occurs during asphalt mix production, transport and compaction at the construction site, all of which happens within hours. It is characterised by relatively high temperatures ( > 130°C) and thus, high oxidation rates. Long-term ageing occurs in asphalt pavements in the field as a result of exposure to traffic and climatic conditions during its service life. Compared to short-term ageing, long-term ageing is a slow oxidation process tha...

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Section: Road Materials and Pavement Designmentioning

confidence: 99%

Effect of short-term ageing temperature on bitumen properties

Hofko

Falchetto

Grenfell

et al. 2017

Road Materials and Pavement Design

102

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“…The existence of ordered agglomerates has been proven by small angle X-ray scattering and small angle neutron scattering experiments [11][12][13] and the nature of asphaltene agglomeration is well established for different solvents, leading to problems and discussions regarding the size of the asphaltenes and their agglomerates [11,[14][15][16]. The existence of a bitumen microstructure and its visualization was performed by various techniques, ranging from confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) to atomic force microscopy (AFM) [17][18][19][20][21][22][23][24][25][26]. A detailed comparison of various imaging technique was performed by Bearsley et al [18].…”

Section: Introductionmentioning

confidence: 99%

Impact of maltene and asphaltene fraction on mechanical behavior and microstructure of bitumen

et al. 2015

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As a widely accepted concept, bitumen consists of four fractions that can be distinguished by their polarity. Highly polar asphaltene micelles are dispersed in a viscous phase of saturates, aromatics and resins (maltene phase). Different concentrations of asphaltenes in the bitumen result in a range of mechanical response properties. In an interdisciplinary study the impact of the maltene phase and asphaltenes on the linear viscoelastic behavior and the microstructure of bitumen were analyzed by creep recovery testing in a DSR and by atomic force microscopy (AFM). Therefore, bitumen was separated into the maltene and asphaltene fractions and artificial bitumen samples with different, pre-defined asphaltene concentrations were produced and investigated. It was found that the artificially produced, precipitated bitumen samples can be regarded as a representative, bitumen-like material in terms of mechanical behavior and microstructure. Asphaltenes play an important role in the typical viscoelastic behavior of bitumen being mainly responsible for stiffness and elasticity. Also, their concentration appears to be correlated to the occurrence and shape of the bee-like inclusions which can be typically observed by AFM.

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“…On the other hand, due to the complexity of its chemical composition, bitumen has been broadly characterized by fractionation techniques (e.g., through thin layer chromatography, TLC/FID) into the so-called "SARAs" fractions (i.e., saturates, aromatics, resins, and asphaltenes), according to their solubility and polarity. Although still a matter of debate, different models have been proposed to describe how these fractions are arranged to constitute the bitumen's microstructure [31]. Among them, the colloidal model is the most realistic to ascertain the effects of esterification and etherification reactions exerted on bitumen's behavior at high in-service temperatures.…”

Section: Physicochemical Characteristics and Microstructure Of Epoxy-mentioning

confidence: 99%

Short- and Long-Term Epoxy Modification of Bitumen: Modification Kinetics, Rheological Properties, and Microstructure

Cuadri¹,

Delgado-Sánchez²,

Navarro³

et al. 2020

Polymers

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Aiming to gain knowledge in the epoxy-bitumen modification mechanisms, this work explores the effects that epoxy concentration and ambient curing exert on the physico-chemistry and thermo-rheological properties of epoxy-modified binders. Process rheokinetics of epoxy-bitumen blends indicates that binder short-term modification (i.e., during processing) is accelerated by epoxy concentration. Furthermore, a synergistic effect of epoxy concentration and ambient curing is found during long-term modification (i.e., during curing at ambient conditions). As a result, viscous and viscoelastic rheological properties of binders are enhanced at medium/high in-service temperatures, at least, after one month of curing. FTIR (Fourier Transform Infrared spectroscopy) tests and SARAs (Saturates, Aromatics, Resins and Asphaltenes) analysis confirm the existence of esterification/etherification reactions between epoxy oxirane groups and the carbonyl groups available in aromatic and resin molecules. Thus, the new high molecular weight compounds increase the asphaltenic fraction of modified bitumen. Likewise, nonreversing heat flow curves obtained by modulated calorimetry corroborate the formation of such highly structured domains responsible for the final binder performance.

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The bitumen microstructure: a fluorescent approach

Cited by 95 publications

References 50 publications

Effect of short-term ageing temperature on bitumen properties

Effect of short-term ageing temperature on bitumen properties

Impact of maltene and asphaltene fraction on mechanical behavior and microstructure of bitumen

Short- and Long-Term Epoxy Modification of Bitumen: Modification Kinetics, Rheological Properties, and Microstructure

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