The Effect Of SBS Block Ratio And Antioxidants On The Performance Of Modified Asphalt

Styrene Butadiene Styrene Block Copolymer(SBS)has become the main asphalt modifier,because of its good heat resistance,low temperature resistance,fatigue resistance performance,etc.Dushanzi Petrochemical Research Institute has developed a kind of linear SBS(T6302H)with good performance.Whereas compared with the commercial SBS(YH791H),the T6302 H has its shortcomings.Through the literature research and study of SBS,it was found that the main factors influencing modifying effect were the microstructure of SBS and the antioxidants in SBS.In this paper,the effect of SBS block ratio to SBS modified asphalt was studied and the antioxidants used for SBS were selected and optimized.Further experiment was conducted to evaluate and verify the application results of SBS modified asphalt.Firstly,through polymerization experiments,SBS with different block ratio could be obtained.The block ratio(S/B),molecular weight and the content of SB of these different SBS could be acquired through Infrared Spectroscopy(IR)and Gel Permeation Chromatography(GCP).The properties of penetration,softening point and ductility of the SBS modified asphalt served as the evaluating indexes,and it was found that the best modification result could be obtained when the SBS block ratio was about 30:70.Secondly,the antioxidants for SBS modifier were selected and optimized through thermal-oxidative aging experiment and SBS modified asphalt experiment.The thermal-oxidative aging experiment result shows that the formulated Irganox1076 with TNPP,Irganox264 with TNPP and Irganox565 with TNPP all had better antioxidant properties than the single antioxidant 1520.Compared with the formulated Irganox1076 with TNPP and Irganox565 with TNPP,the formulated Irganox264 with TNPP had poor antioxidant property.Then the experiment of the SBS modified asphalt was conducted to study the modification effect of different antioxidants,and it was found that the effect of the formulated Irganox1076 with TNPP and Irganox565 with TNPP to the SBS modified asphalt were about the same.Considering the economic factors,the application results of the formulated Irganox565 with TNPP was considered to be better than that of the formulated Irganox1076 with TNPP.Finally,based on the above experiment results,SBS modifier(block ratio of 30:70)with the formulated Irganox565 with TNPP was used for modification of asphalt.Then the experiment of SBS modified asphalt was conducted on Tahe base asphalt and mixedasphalt respectively to verify the above experiment results.The results showed that the performance of modified asphalt was good and met the I-C specification in the standard(JTG F40-2004)in “ Technical Specifications for Construction of Highway Modified Asphalt Pavement ” issued by the Ministry of comminucations of the People's Republic of China,comparable with the performance of YH791 H modified asphalts.