Applicability of time-temperature superposition for laboratory-aged neat and SBS-modified bitumens

Apparent Molecular Weight Distributions for Investigating Aging in Polymer-Modified Bitumen

“…After 25 hours of aging, the Black diagram presents only a few irregularities and the symptoms of the inapplicability of TTSP disappear after long-term aging. These trends are in accordance with previous observations made with the SBS copolymer [43].…”

“…The applicability of the TTSP in the case of unmodified binders is well accepted and documented [35,[40][41][42], whereas using the TTSP for PMBs is still an open issue. Cuciniello et al [43] showed that for bitumens modified with high contents of poly(styrene-butadiene-styrene) block copolymer (SBS), using the TTSP can be difficult especially in unaged binders with a high polymer content due to the integrity of the complex structure formed by the polymeric network which is swollen with bitumen molecules. The polymer has an elastomeric behaviour throughout the entire working temperature range.…”

Ageing Effects on a Softened Bitumen by the Addition of DSA (Dodecenyl Succinic Anhydride)

“…According to the decrease observed of more than 5 • C in the glass transition temperature for the systems containing additives, a notable performance improvement is expected. Therefore, these results demonstrate that DSA and oil make bitumen less stiff, which is a necessary condition to ensure that the rejuvenator addition compensates for the deteriorated mechanical properties, in order to avoid cracking failures in asphalt pavement [21][22][23]. In addition, once again, Figure 1 points out the greater efficacy of DSA when softening a model bitumen, so as to mechanically rejuvenate it.…”

“…In line with this, as shown in Table 3, the temperature at which the binder passes the Superpave rutting parameter criterion for unaged samples (|G*|/sinδ = 1 kPa) also undergoes a reduction of almost 4 • C after additivation. Moreover, in the low-temperature region, the so-called "mechanical" glass transition, as defined in correspondence with the temperature at which G′′ reaches a maximum in the glassy zone at 10 rad/s [21][22][23], (see Figure 2), has been gathered in Table 4 for each system. According to the decrease observed of more than 5 °C in the glass transition temperature for the systems containing additives, a notable performance improvement is expected.…”

“…Table 3 illustrates the limiting temperature at which thermal cracking is expected, as established by In general, in the case of bituminous products, superposition principle does not always give rise to a smooth master curve, pointing out a deviation from a thermorheologically simple behaviour. This is not surprising, given the structural complexity and heterogeneity of bitumen, with the presence of dispersed phases which may undergo structural changes in the transition zone, as in the cases of highly crystalline bitumens (wax contents > 7 wt.%), structured bitumens with high asphaltene contents and highly polymer-modified bitumens [22].…”