Macrostructure and Rheological Properties of Chemically Modified Residues and Bitumens

Giavarini, Carlo; Mastrofini, D.; Scarsella, Marco; Barré, Loı̈c; Espinat, D.

doi:10.1021/ef9902045

Cited by 81 publications

(49 citation statements)

References 40 publications

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“…However, there was no frequency independent zone observed for the unmodified bitumen. Nevertheless, this is used as a parameter to identify the transition temperature as frequency independent tan d has been observed for modified bitumen such as polyphosphoric acid modified bitumen [5].…”

Section: Introductionmentioning

confidence: 99%

What is Transition Temperature for Bitumen and How to Measure It?

Nivitha

Krishnan

2016

Transp. in Dev. Econ.

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In a typical year and for any typical location in India, the lowest temperature of the pavement can go up to 0°C or below and the highest temperature can reach up to 70°C or above. During such temperature changes, the binder exhibits behaviour ranging from a glassy material (at lower temperature) to a viscoelastic/non-Newtonian fluid (at higher temperature). The range of temperature change which is of interest to a pavement engineer is the transition between viscoelastic solid to viscoelastic fluid. Two measurements are normally used for quantifying the transition temperature and they are the G 0 -G 00 cross over point and the point when tan d is independent of frequency (Winter-Chambon criterion). These measures are applicable when the material has a single relaxation time (typically a single constituent material). Since bitumen is a mixture of several complex hydrocarbons each with different relaxation time, it is natural that such measures are also frequency dependent. This investigation will focus attention on determining the frequency dependence of G 0 -G 00 cross over point as well as the relationship of tan d with frequency. An unmodified binder of VG30 grade as per IS73-2013 and a crumb rubber modified binder of meeting CRMB 60 grade as per IS:15462-2004 were used in this investigation. To estimate the viscoelastic solid-fluid transition temperature, frequency domain tests were performed in the temperature range of 25-75°C for frequencies in the range of 50-1 Hz. All the tests discussed in this study were performed at two aging conditions, unaged and short-term aged. Due to the frequency dependent nature of bitumen, the transition temperature is not a sharp point as in the case of polymers but occurred gradually over a temperature range. Contrary to what one expected, modification process did not drastically change the transition temperature and one could see a change of only 3°C for CRMB 60 when compared to VG30. Aging of the modified bitumen proportionally shifted the transition temperature in a similar manner to that of the unmodified bitumen. It was also clearly seen that the Winter-Chambon criterion was not met for all the binders investigated in this study.

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Section: Introductionmentioning

confidence: 99%

What is Transition Temperature for Bitumen and How to Measure It?

Nivitha

Krishnan

2016

Transp. in Dev. Econ.

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“…However, a previous blend of phosphogypsum with the asphaltic bitumen, before this is used as binder of the mineral aggregates, may result of higher interest, as phosphorus compounds are well-known to improve its high temperature performance if compared to the original bitumen [11][12][13]. Consequently, the above alternative does not represent a disadvantage for the environment.…”

Section: Introductionmentioning

confidence: 99%

Valorization of phosphogypsum waste as asphaltic bitumen modifier

Cuadri

Navarro

García‐Morales

et al. 2014

Journal of Hazardous Materials

117

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The accumulation of phosphogypsum wastes from the fertilizer industries, which remain in regulated stacks occupying considerable land resources, is causing significant environment problems worldwide. In that sense, the scientific community is being pressured to find alternative ways for their disposal. In this research, we propose a novel application for phosphogypsum wastes, as a modifier of bitumen for flexible road pavements. Viscous flow tests carried out on bitumen modified with a phosphogypsum waste and doped with sulfuric acid demonstrated an extraordinary increase in viscosity, at 60 ºC, when compared to a counterpart sample which had been modified with gypsum, the main component of phosphogypsum. Similarly, a significant improvement in the viscoelastic response of the resulting material at high temperatures was also found. FTIR (Fourier transform infrared spectroscopy) scans provided evidences of the existence of chemical reactions involving phosphorus, as revealed by a new absorption band from 1060 to 1180 cm -1 , related to C−O−P vibrations. This result points at phosphorus contained in the phosphogypsum impurities to be the actual "modifying" substance. Furthermore, no C-O-P band was observed in the absence of sulfuric acid, which seems to be the "promoting" agent of this type of bond.

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“…Illustrative examples are the use of sulphur (Smagulova et al 2012), polyphosphoric acid (Masson 2008), mineral acids (Giavarini et al 2000) or waxes (Tasdemir 2009). However, bitumen modification for paving applications is mostly carried out by means of polymers, both virgin (polyethylenes, EVA, SBS, SBR, etc.)…”

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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Macrostructure and Rheological Properties of Chemically Modified Residues and Bitumens

Cited by 81 publications

References 40 publications

What is Transition Temperature for Bitumen and How to Measure It?

What is Transition Temperature for Bitumen and How to Measure It?

Valorization of phosphogypsum waste as asphaltic bitumen modifier

The development of polyurethane modified bitumen emulsions for cold mix applications

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