Formation of equilibrium structures in bitumens

The colloidal structure of bitumen: Consequences on the rheology and on the mechanisms of bitumen modification

“…More recently, it was observed that steric hardening occurs with a slight volume contraction, of order of 0.1% in 5 h [185], with the fastest rate between 20 and 80°C occurring at 50°C. The kinetics of volume contraction followed an Avrami law with exponent between 1 and 1.2, which is generally interpreted as the growth of linear crystals [185].…”

“…The kinetics of volume contraction followed an Avrami law with exponent between 1 and 1.2, which is generally interpreted as the growth of linear crystals [185].…”

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.…”

“…However, the degree of order and the perfection of the particles of the new phase which was formed were not high. Complete crystallization was absent, the observed change in density was small (about 0.55 %) and the time constant was about 6 h [16].…”

“…Previous investigations of crystallization kinetics of bitumen binders in bulk covering a time scale of days and using dilatometry resulted in a value of the Avrami parameter equal to 1, independent on the composition or hardness (PEN-grade) of the bitumen samples [16]. It was observed, that the change in bitumen density occurred most rapidly at 50°C i.e., at the temperature which is also characteristic for the maximum change in shear stress (softening).…”