Accelerated short-term ageing effects on the rheological properties of modified bitumens with similar high PG grades

作者：Inocente Domingos Matheus David; Faxina Adalberto Leandro

来源：Road Materials and Pavement Design, 2015, 16(2): 469-480.

DOI：10.1080/14680629.2014.995209

• phase angle
• ageing index
• modified bitumens
• performance grade
• short-term ageing
• complex shear modulus

The main purpose of the study was to evaluate the effects of rolling thin-film oven (RTFO) ageing on some rheological properties of modified bitumens. They are graded as PG 76-xx and were obtained from a 50/70 bitumen graded as PG 64-xx. Three types of polymers - polyethylene (PE), styrene-butadiene-styrene (SBS) copolymer and ethylene butylacrylate glycidylmethacrylate (Elvaloy((R))) terpolymer - and polyphosphoric acid (PPA) were selected. Ageing mainly increased the complex modulus (G*) and decreased the phase angle (delta) of the bitumens, thereby increasing their stiffness and elasticity. The existence of plateau regions in the master curves of delta for the bitumen+Elvaloy+PPA and the bitumen+SBS can be explained by the distinctive characteristics of the modifiers, since these plateaus were not observed for the other bitumens. The bitumen+SBS and the bitumen+PE showed very high sensitivity to ageing from the point of view of G* and delta, and the opposite is observed for the conventional properties.

• 出版日期2015-4-3