Bitumen in colloid science: a chemical, structural and rheological approach

Loeber, L.; Müller, G.; Morel, J.; Sutton, O.

doi:10.1016/s0016-2361(98)00054-4

Cited by 322 publications

(171 citation statements)

References 11 publications

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“…However, the chemical composition and origin of the observed phases is a -17 -controversial topic and a matter of debate. In this sense, some authors postulate that the bee-structures consist of the most polar fraction of bitumen [22,35] and so they resemble the colloidal model. On the other hand, others authors have attributed the "bee" structures as the result of co-precipitation of non-wax asphalt compounds with crystallizing non-polar waxes [34,36].…”

Section: Chemical Modification and Microstructurementioning

confidence: 99%

Processing of bitumens modified by a bio-oil-derived polyurethane

Cuadri¹,

García‐Morales²,

Navarro³

et al. 2014

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Castor oil (CO) functionalized by isocyanate groups (-NCO) is proposed as a novel bio-based reactive polyurethane (PU) for bitumen modification. This work presents a comparative analysis conducted on blends of bitumen and 2 wt.% of a PU prepolymer prepared by NCO-functionalization of castor oil. Four preparation procedures were evaluated, which resulted from the combination of two processing times (1h or 24h, at 90ºC) followed by two different post-treatments (water addition or ambient curing for up to 6 months). It was found that the degree of modification attained after posttreatment depends on the previous processing conditions. Thus, short processing times are required if the binder is further subjected to ambient curing. Instead, the success of the water-addition modification falls on a previous long processing step. As revealed by rheological tests, ambient curing was seen to be by far a more efficient way of modification if compared to direct addition of water, and makes clear that the resulting binder evolves towards a better performance when in service. In that sense, Thin Layer Chromatography tests, Modulated DSC and AFM images demonstrated a more complex microstructure characterized by the presence of a larger content of molecules with higher polarity, size and molecular weight.

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Section: Chemical Modification and Microstructurementioning

confidence: 99%

Processing of bitumens modified by a bio-oil-derived polyurethane

Cuadri¹,

García‐Morales²,

Navarro³

et al. 2014

Fuel

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“…This can be used to efficiently visualize the microstructure of bitumen [5,18,21,33] and structural effects of bitumen modification [14,29,47,54]. Bearsley et al presented a very detailed comparison of CLSM with other imaging techniques [5].…”

Section: Introductionmentioning

confidence: 99%

The bitumen microstructure: a fluorescent approach

et al. 2014

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Five bituminous samples were carefully studied by confocal laser scanning microscopy using 488 nm excitation radiation and observing 500-530 nm of emission. The images revealed the microstructure of bitumen. The influence of the admixture of mineral aggregates concerning the microstructure was tested. For the minerals, no significant influence was found. For understanding the origin of fluorescent signals, the samples were separated into asphaltenes and maltenes and analyzed with fluorescence spectroscopy. Although former works have assumed the origin of fluorescent emissions in bitumen to be found in the asphaltene fraction, the asphaltenes produce little to no emissions, but the maltenes exhibit strong fluorescence in the observed spectral region. For deeper insight, fractionation of the bitumina into the SARA fractions by chromatographic column separation was necessary. The fluorescence spectra of these fractions were analyzed and revealed the aromatics and resin phases to be the only components capable of sufficiently intense fluorescent emission. This is a strong argument for a complex internal microstructure consisting of a mantle of aromatics surrounding an inner core.

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“…From previous research, it was found that the concentration of asphaltene usually varies from 5 to 25% in bitumen [14] which in turn depends on the origin of the oil crude source. Usually, asphaltene content in the range of between 5 -25% is considered as moderate range, which exhibit sol-gel characteristics basically responsible for their viscoelastic properties [15].The sol-gel characteristic of bitumen is considered beneficial as characterized by delay in the elastic deformability that will help in accommodating larger stresses in pavement because of the considerable degree of elastic deformation [16].From Table 1 it is inferred that aspahltene content for virgin bitumen was found to reduces gradually from 15% to 13.56% with the addition of polymer in bitumen. This decrease in asphaltene content indicates that the high molecular weight micelle becomes more peptized [16] or stabilized by the addition of polymer in the blend as observed by decrease in colloidal Index (CI), as presented in Table 1 enhancing the pseudo plastic behaviour of the blend which is very commonly observed for polymeric solution [17].…”

Section: Asphaltene Content Analysis (Astm D 3279)mentioning

confidence: 99%

Investigation on the effect of phase segregation on the mechanical properties of polymer modified bitumen using analytical and morphological tools

et al. 2017

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Abstract. The mechanical strength of polymer modified bituminous mix which is evaluated in terms of stiffness reflects the deformation behaviour of bituminous mixture. The stiffness of the binder strongly depends on its chemical composition besides aggregate structure of the bituminous mixture. Compatibility of polymer with the base bitumen is considered as major strength enhancing factor in the case of polymer modified bituminous mix. To relate the factors affecting the mechanical strength of the binder a new approach in this research study was adopted in order to relate the compatibility of 80/100 pen bitumen with polymer Polypropylene (PP) using analytical and morphological tools. Morphological tools like Atomic Force Microscopy (AFM) and Transmission Electron Microscope (TEM) were used to study the changes due to the difference in compatibility of polymer with bitumen. It was observed that the presence of phase segregated layer as observed by AFM surface morphology was considered as the main strength enhancing factor of the bituminous mix. While the presence of lamella as observed in TEM scanned images of PP PMB revealed that addition of polymer forms localized network in the phase segregated layer which induces the stiffening effect in PMB. From the chromatographic method (SARA) analytical analysis Saturate, Aromatics, Resin and Asphaltene fractionate were determined in the blend. It was observed that chemical composition of the blend also has a profound effect on the rheological properties and on the morphology of polymer modified bituminous (PMB) blend. It was concluded that PP PMB gets benefited by phase segregated layer in the blend when the polymer concentration was kept below 3% as it sufficiently enhances the mechanical strength of the PMB binder as observed by dynamic creep results.

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Bitumen in colloid science: a chemical, structural and rheological approach

Cited by 322 publications

References 11 publications

Processing of bitumens modified by a bio-oil-derived polyurethane

Processing of bitumens modified by a bio-oil-derived polyurethane

The bitumen microstructure: a fluorescent approach

Investigation on the effect of phase segregation on the mechanical properties of polymer modified bitumen using analytical and morphological tools

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