Steric Hardening and the Ordering of Asphaltenes in Bitumen

Abstract

/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10.1021/ef0498667 Energy & Fuels, 19, 1, pp. 120-122, 2005-01-01 Steric hardening and the ordering of asphaltenes in bitumen Masson, J-F.; Collins, P.; Polomark, G. M. Steric hardening and the ordering of asphaltenes in bitumenMasson, J-F.; Collins, P.; Polomark, G. NRCC-47288 AbstractSteric hardening is the hardening of bitumen over time at room temperature. It occurs after bitumen is melted and it often leads to poor reproducibility in standard testing.Modulated differential scanning calorimetry shows that asphaltenes order when bitumen is cooled from the melt and that this phenomenon is time dependent. This communication establishes the link between the ordering of the asphaltenes in bitumen and its steric hardening. It is suggested that at least 24 h elapse between the melting and pouring of bitumen and its subsequent testing by standardized methods.

Fast solidification kinetics of parts of bituminous binders

“…The beginning of the crystallization is homogeneously nucleated and three-dimensional, which changes in the course of crystallization to 2-dimensional crystal growth and mixed nucleation, both homogeneous and heterogeneous. The primary crystallization process is very fast and followed by subsequent hardening events as reported by Pechenyi and Kusnetzov [16] and by Masson et al [8,17]. This especially the case in the Total bitumen sample, which crystallizes very fast and reaches also an initially higher degree of crystallinity compared to the Q8 sample.…”

“…Crystallisation starts almost immediately after or instantaneously during cooling. An earlier study by Masson et al [17]. proposed liquid liquid demixing within bitumen upon cooling resulting finally in steric hardening.…”

Starenje vrućih asfaltnih mješavina

“…The oxidation leads to an increased fragility and appearance of cracks in the asphalt layer [15]. Steric hardening of bitumen takes place over time at room temperature resulting in the molecular rearrangement in bitumen [16]. Physical hardening results in an increase in viscosity and appearance of volume contractions.…”

“…Steric hardening refers to the hardening of bitumen at room temperature, due to molecular rearrangement in the binder [33]. In their paper, Masson et al [33] note that the time period between the heating, pouring and testing must be at least 24 hours, so that a good bitumen testing repeatability can be achieved.…”

“…In their paper, Masson et al [33] note that the time period between the heating, pouring and testing must be at least 24 hours, so that a good bitumen testing repeatability can be achieved. In their study, Guern et al (2010) examine physical and mechanical properties of five different types of bitumen prior to and after ageing [34].…”