Effect of Layered Double Hydroxides on Ultraviolet Aging Resistance of SBS Modified Bitumen Membrane

Layered double hydroxides （LDHs）/styrene-butadiene-styrene （SBS） eopolymer modified bitumen was prepared by melt blending. The effect of LDHs on the ultraviolet （UV） aging behavior of SBS modified bitumen was investigated. The changes of chemical structures of modified bitumen before and after UV aging were characterized by Fourier transform infrared spectroscopy （FTIR）. The results show that LDHs obviously reduce the variation of softening point and low temperature flexibility of SBS modified bitumen under different UV radiation intensities, which indicates that the UV aging resistance performance of SBS modified bitumen is improved effectively by LDHs. Compared with SBS modified bitumen, the changes of carbonyl, sulfoxide and butadienyl of LDHs/SBS modified bitumen decrease significantly after UV aging according to FTIR analysis, demonstrating that the oxidation and degradation reactions of SBS modified bitumen were restrained effectively by adding LDHs.

Effect of Organophilic Montmorillonite on Thermal-oxidative Aging Behavior of SBS Modified Bitumen Crack Filling Material

Styrene-butadiene-styrene （SBS） modified bitumen crack filling material with organophilic montmorillonite （OCFM） was prepared by melt blending. X-ray diffraction analysis shows that the interlayer spacing of organophilic montmorillonite （OMMT） in OCFM is widened and an exfoliated structure may be formed. Thermal-oxidative aging behavior of OCFM and SBS modified bitumen crack filling material （SCFM） was investigated. The experimental results indicate that the rate of thermal-oxidative aging of OCFM is much slower than that of SCFM, which can be attributed to barrier of exfoliated structure of OCFM to oxygen.

Investigation of internal phases of linear SBS modified bitumen at the nanoscale using AFM PF-QNM

Currently,few studies explore the internal phases of styrene-butadiene-styrene(SBS)modified bitumen at the nanoscale,though the surface phases of SBS modified bitumen have been deeply understood through a lot of research.The present study uses the atomic force microscopy(AFM)peak force quantitative nanomechanical mode(PF-QNM)to investigate the nanomechanical properties of the interior of linear SBS modified bitumen and corresponding mastics at the nanoscale.Firstly,the suitable experimental methods for the interior of bitumen and mastics are explored.Then,the phase relationship between surfaces and interiors of linear SBS modified bitumen is determined by analyzing nanomechanical properties.On this basis,in comparison with the internal phases of base bitumen,the effect of modifiers on phases is deeply investigated.Finally,the internal phases of linear SBS modified bituminous mastics are further investigated.The results reveal that the interior of linear SBS modified bitumen only has two phases,which form in a manner like periphase and paraphase on the surface.In contrast to base bitumen,linear SBS modified bitumen does not create new phases and change the properties of original phases in the interior,but affects the proportion of A-phase and B-phase and presents the homogenization.Furthermore,due to the influence of preparation methods,only the bitumen area away from the fillers can be imaged by AFM PF-QNM.It can be found that the addition of mineral fillers also slightly changes the internal phase distribution of linear SBS modified bitumen,while the effect is less than that of fillers on base bitumen.