Influence of Bitumen Colloidal Nature on the Design of Isocyanate-Based Bituminous Products with Enhanced Rheological Properties

Carrera, Virginia; Partal, P.; García‐Morales, M.; Gallegos, C.; Páez, Antonio

doi:10.1021/ie9004404

Cited by 46 publications

(39 citation statements)

References 21 publications

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“…However, if temperature is further increased, tanδ is also seen to experience an exponential increase (not shown in the temperature interval studied in Figure 3) as expected from the terminal region. Interestingly, the transition above disappears after water addition or long curing [26,27].…”

Section: In-service Performance Of the Modified Bitumensmentioning

confidence: 99%

“…Figure 7 shows the evolution of the "modified" colloidal index values for the modified binders studied. According to the C.I.mod defined above and to the bitumen colloidal model, a higher index value would be related to a material which exhibits a more significant solid-like behaviour [20,23,26,27]. Longer curing times, above all after only 1h of processing, enhance the material's microstructure (larger quality of its colloidal microstructure or a more solid-like behaviour).…”

Section: Chemical Modification and Microstructurementioning

confidence: 99%

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

Cuadri¹,

García‐Morales²,

Navarro³

et al. 2014

Fuel

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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: In-service Performance Of the Modified Bitumensmentioning

confidence: 99%

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

View full text Add to dashboard Cite

show abstract

“…However, the material hardens with time. Even though ''fresh'' emulsions can satisfactorily perform as such from the very first moment (compare the large differences in viscosities, at 60ºC, for neat bitumen and residues in Figure 5), Carrera et al (2009) demonstrated that in-service curing makes these binders evolve towards a better performance against the permanent deformation. In contrast, manufacturing of emulsions with other PMBs may be especially delicate, as processing temperature has to be very high for the PMBs to have a viscosity of about 200 mPa·s (Lesueur 2011).…”

Section: Rheology Of the Emulsion Residuesmentioning

confidence: 99%

“…In order to resolve these problems, we propose to conduct a reactive modification with an isocyanate-functionalized polypropylene glycol, a liquid with low viscosity which allows both mixing with bitumen and further emulsification to be carried out between 80 and 90ºC in an open vessel. This prepolymer has shown to produce an important increase in the binder viscosity as a consequence of ambient curing once in service (Carrera et al 2009). …”

Section: Introductionmentioning

confidence: 99%

The development of polyurethane modified bitumen emulsions for cold mix applications

et al. 2014

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Bitumen emulsions stand for an alternative paving practice to the traditional hot-mix asphalts. In addition, modified bitumen emulsions show a better performance than unmodified ones. This work studies the feasibility of obtaining polyurethane modified bitumen emulsions, in which an isocyanate-functionalized polyol constitutes the bitumen modifier (in varying concentration from 1 to 4 wt.%). Storage stability and high in-service performance are evaluated by means of evolution of droplet size distribution (DSD) and rheology tests, respectively. Regarding the emulsion stability, the key factor seems to be the bitumen modifier concentration used to prepare the modified emulsions. Thus, for a selected 50 wt.% bitumen fraction, there is a limit concentration (between 1 and 2 wt.%) above which the emulsion becomes unstable under storage. Hence, this result limits the modifier content that can be used in the emulsion and the final level of modification achieved if compared to the original nonmodified emulsion. On the other hand, the rheological characterization conducted on the emulsion residues at 60ºC has shown an improved resistance to deformation.In terms of applicability, polyurethane modified bitumens allows for the obtaining of modified emulsions which can be prepared at much lower temperatures than those derived from other polymers.

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“…Other no-common additives employed in the bitumen modification are waste polymer [7,8] (plastic from agriculture, crumb tyre rubber, etc. ), sulphur [9] or polyurethanes [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Chemically modified bitumens with enhanced rheology and adhesion properties to siliceous aggregates

Cuadri¹,

Partal²,

Ahmad

et al. 2015

Construction and Building Materials

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Moisture damage is one of the major premature failures that worsens the performance and shortens service life of pavements. This research assesses the effect that two chemical modifiers (thiourea and an isocyanate-functionalized castor oil prepolymer) exerts on the bitumen rheology and on the resistance to potential moisture damage of asphalt mixtures based on siliceous aggregates. Both thiourea and the isocyanate-based prepolymer improve the viscous and viscoelastic behaviours of bitumen at high inservice temperatures, particularly the isocyanate-based reactive modifier. Likewise, the visual inspection of the degree of bitumen coating on loose mixtures exposed to water in a "rolling bottle" test, and further surface free energy measurements, showed that the bitumen modification by the isocyanate-based prepolymer seems to reduce moistureinduced damage on siliceous aggregates. Conversely, thiourea-based modification increases sensitivity of the bitumen-aggregate mixture to water. Different adhesion mechanisms, based on chemical or physical bonds with the aggregate surface, have been proposed for each modifier.

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Influence of Bitumen Colloidal Nature on the Design of Isocyanate-Based Bituminous Products with Enhanced Rheological Properties

Cited by 46 publications

References 21 publications

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

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

The development of polyurethane modified bitumen emulsions for cold mix applications

Chemically modified bitumens with enhanced rheology and adhesion properties to siliceous aggregates

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