This work investigated the aging effects on the rheological properties of high viscosity modified asphalt(HVMA).First,the high-and low-temperature rheological properties were measured by a dynamic shear rheometer and ...This work investigated the aging effects on the rheological properties of high viscosity modified asphalt(HVMA).First,the high-and low-temperature rheological properties were measured by a dynamic shear rheometer and a bending beam rheometer,respectively.The aging mechanism was then tested using an Fourier transform infrared spectroscopy and a scanning electron microscope.Besides,a study was performed to compare the aging effects on the rheological properties of HVMA,crumb rubber modified asphalt(CRMA),and neat asphalt(SK-90).The experimental results showed that the effects of the long-term aging on HVMA exceeded those of short-term aging.The complex shear modulus of the HVMA was improved by the aging in the whole frequency range.The complex shear modulus of the HVMA after the long-term aging was larger than after the short-term aging.Thus,the aging improved the high-temperature viscoelastic performance of HVMA.With a decrease in temperature from-12℃to-24℃,the low-temperature viscoelastic performance of HVMA decreased since its stiffness modulus and low continuous grading temperature increase.Both of the short-and long-term aging of HVMA were caused by an oxidation reaction,while modifier swelling also happened after long-term aging.Compared to CRMA and SK-90,aging had a limited influence on the high-and low-temperature rheological properties of HVMA.展开更多
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 resea...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.展开更多
基金supported by the National Key R&D Program of China(Grant No.2018YFB1600200)the Fok YingTong Education Foundation(Grant No.161072)+1 种基金the Youth Top-notch Talent Support Program of Shaanxi Provincethe Fundamental Research Funds for the Central Universities(Grant No.300102219317)。
文摘This work investigated the aging effects on the rheological properties of high viscosity modified asphalt(HVMA).First,the high-and low-temperature rheological properties were measured by a dynamic shear rheometer and a bending beam rheometer,respectively.The aging mechanism was then tested using an Fourier transform infrared spectroscopy and a scanning electron microscope.Besides,a study was performed to compare the aging effects on the rheological properties of HVMA,crumb rubber modified asphalt(CRMA),and neat asphalt(SK-90).The experimental results showed that the effects of the long-term aging on HVMA exceeded those of short-term aging.The complex shear modulus of the HVMA was improved by the aging in the whole frequency range.The complex shear modulus of the HVMA after the long-term aging was larger than after the short-term aging.Thus,the aging improved the high-temperature viscoelastic performance of HVMA.With a decrease in temperature from-12℃to-24℃,the low-temperature viscoelastic performance of HVMA decreased since its stiffness modulus and low continuous grading temperature increase.Both of the short-and long-term aging of HVMA were caused by an oxidation reaction,while modifier swelling also happened after long-term aging.Compared to CRMA and SK-90,aging had a limited influence on the high-and low-temperature rheological properties of HVMA.
基金This work was supported by the National Natural Science Foundation of China(grant number 52108394,51978521)the Young Talent Fund of University Association for Science and Technology in Shaanxi,China(grant number 20220419)the Key Research and Development Program of Shaanxi,China(grant number 2023-YBGY-491).
文摘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.
