Abstract
The objectives of this paper are twofold: to evaluate rheological and chemical changes induced by the oxidative ageing of SBS modified bitumen and to compare with changes measured by conventional methods such as softening opint. In particular, in this study, three bitumen, from different crude origin, were blended with the same SBS block copolymer. After chromatography (GPC) show little difference between the different blends, which also have similar softening points. After ageing, differences both in the molecular weight chanes of the polymer and in the stiffening of the bitumen are found. The rheological measurements show the combined effects of bitumen stiffening and polymer network reduction, changes in softening points are still in line with the molecular weight changes softening points are still in line with the molecular weight changes of the polymer observed by GPC. A second ogjective of this paper is to compare the "ageing strength" of two different ageing proceudres. In particular the pressure ageing vessel (PAV), as developed by SHRP for the accelerated long-term ageing of road bitumen, was used and compared with more traditional long-term ageing procedures. In addition, measurements on recovered roofing material after different years of service life were performed and compared with laboratory aged samples.
The objectives of this paper are twofold: to evaluate rheological and chemical changes induced by the oxidative ageing of SBS modified bitumen and to compare with changes measured by conventional methods such as softening opint. In particular, in this study, three bitumen, from different crude origin, were blended with the same SBS block copolymer. After chromatography (GPC) show little difference between the different blends, which also have similar softening points. After ageing, differences both in the molecular weight chanes of the polymer and in the stiffening of the bitumen are found. The rheological measurements show the combined effects of bitumen stiffening and polymer network reduction, changes in softening points are still in line with the molecular weight changes softening points are still in line with the molecular weight changes of the polymer observed by GPC. A second ogjective of this paper is to compare the "ageing strength" of two different ageing proceudres. In particular the pressure ageing vessel (PAV), as developed by SHRP for the accelerated long-term ageing of road bitumen, was used and compared with more traditional long-term ageing procedures. In addition, measurements on recovered roofing material after different years of service life were performed and compared with laboratory aged samples.
Date
10/2000
10/2000
Author(s)
Hilde Soenen; Bengt Sandman; Ann-maj Nilsson
Hilde Soenen; Bengt Sandman; Ann-maj Nilsson
Page(s)
24-46
24-46
Keyword(s)
oxidative aging; SBS; modified bitumen; softening point; aging strength
oxidative aging; SBS; modified bitumen; softening point; aging strength