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Increases in traffic density and axle loading in combination with a pressure to reduce material costs has created high performance requirements for asphalt pavements.
In sustainable asphalt road construction, proper selection of materials is of great importance. A durable material along with optimal mix and pavement design is crucial to a long lifetime of asphalt pavements. For bituminous binders, increased experience and knowledge has been seen on use of polymer modification. The main objective of this paper is to study the durability of polymer modified binders in terms of resistance to aging, rutting and cracking.
It was found that the polymer modified binders demonstrate better rheological properties than unmodified pen bitumen, even after several years in asphalt pavements. These improvements include higher strain recovery and lower non-recoverable compliance (Jnr) at high temperatures, and lower stiffness at low temperatures. For the modified binders with styrene-butadiene-styrene (SBS) polymers, good aging resistance was also observed. The improved binder properties should be beneficial in terms of resistance to asphalt rutting and cracking. This is expected to be confirmed by a longer time of follow-up on the performance of the test road.
Asphalt samples were taken from test roads where polymer modified binders were tested in different layers. Field samples were analysed with respect to binder contents and air void contents. In characterisation of recovered binders various tests were carried out, including time-temperature sweeps and multiple stress creep and recovery test (MSCR) using dynamic shear rheometer, gel permeation chromatography, Fourier transform infrared spectroscopy, fluorescence microscopy, as well as conventional tests such as penetration. The chemical and mechanical tests were also conducted on original binders and those aged at laboratory by RTFOT and PAV.
Read Paper: Durability of polymer modified binders in asphalt pavements
Xiaohu Lu, Hilde Soenen, Serge Heyrman and Per Redelius, Nynas