Preparation And Properties Of UV Absorber Residue Modified Bitumen

As pavement material,asphalt has been widely used in road construction,but in the processing and service period,it is subjected to aging phenomena due to the influence of processing conditions and natural environment,which greatly reduces its road performance and shortens the lifetime of pavement.Ultraviolet absorber has a significant effect in improving asphalt aging resistance because of its outstanding ultraviolet absorption performance,but the high price limits its wide application in asphalt modification.It will produce plenty of UV absorber residue which contains a certain amount of UV absorber in the synthesis process of ultraviolet absorber.Actually,the residue is still provided of the UV absorption performance.Dealing with UV absorber residue will not only increase the cost of production,but also lead to environmental pollution.It has important research value and practical significance that UV absorber residue is used for asphalt modification.Two kind of UV absorber residues modified pristine bitumen and UV absorber residue/SBS modified bitumen were prepared by melt blending in this paper.In the same time,thin film oven(TFOT)ageing and ultraviolet aging test were conducted.The effects of UV absorption residue on physical properties,rheological properties,chemical composition and ageing properties of bitumen are investigated.Chemical structure and microstructure of bitumen were evaluated by fourier transform infrared(FTIR)and fluorescence microscope.The main research conclusions are as follows:(1)There is a certain effect of UV absorber residue on physical properties of pristine bitumen and SBS modified bitumen.Softening point and viscosity of bitumen become larger with the introduction of decolorizing activated carbon residue(B2HG),as the penetration and ductility decrease.The B2 HG improves the high temperature performance of bitumen.The recrystallization residue(AZJG)make the softening point and viscosity of bitumen decreased and the penetration and ductility larger.It shows that AZJG can enhance the low temperature performance of bitumen.(2)UV absorber residue make significant effects on the dynamic shear rheological properties of the pristine bitumen and SBS modified bitumen.The complex shear modulus(G*)of bitumen is increased by the addition of B2 HG,andthe phase angle(?)becomes smaller obviously..AZJG decreases the G* of bitumen,and makes the phase angle increased.In contrast,the influence of B2 HG on G* of SBS modified is more obvious and the effect of AZJG on SBS modified asphalt is greater than that of pristine bitumen.(3)The two kinds of UV absorber residue have an obvious improvement on the short-term thermal oxygen aging resistance and UV aging resistance of the pristine bitumen and SBS modified bitumen.Compared with the pristine bitumen and SBS modified bitumen,the UV absorber residue modified bitumen shows lower VAI and SPI values,and DRR is obviously bigger than that of bitumen without residue after TFOT and UV aging.Meanwhile,B2 HG and AZJG can also inhibit the G* getting larger and ? becoming smaller during the TFOT and UV ageing.Compared with AZJG,B2 HG can inhibit the decay of physical and rheological properties of asphalt in a much greater degree.(4)SARA(saturates,aromatics,resins and bitumenenes)analysis show that the addition of B2 HG decreases the content of saturates and aromatics in bitumen,and resins content declines.AZJG increases the content of light components significantly,and decreases the content of resin and asphaltene with larger molecular weight.B2 HG and AZJG both retard the change of the component content during the ageing,and restrain the transformation from lighter compositions of bitumen to the hard ones.(5)FTIR results show that B2 HG reduces the relative content of branched aliphatic functional groups and aromatic functional groups in pristine bitumen,and the relative content of aromatic functional groups in SBS modified asphalt gets smaller with the addition of B2 HG.In addition,B2 HG can significantly reduce the changes of functional group index during TFOT and UV aging,and inhibit the oxidation,polycondensation and chain rupture resulted from ageing.Fluorescence microscopy measurements show that aging leading to serious degradation of SBS,and UV absorber residue can inhibit the damage of SBS network structure.