The Research On Mechanism Of Pyrolytic Carbon Black From Used Tire Asphalt

This article relies on the opening topic of "Research on the Mechanism of Pyrolytic Carbon Black from Used Tire Asphalt" by the Key Laboratory of Road Structures and Materials Transportation Industry(Beijing),to study the chemical modification of recycled carbon black and its amount in asphalt,uses IR to study the physicochemical properties in the blending process of PCB and asphalt;uses Laser Particle Size Analyzer Determination of Particle Distribution Before and After Chemical Modification of PCB;X-ray Diffraction Analysis of the Phase Structure of PCB and PCB Modified Asphalt;Electron Microscope Scanning to Observe Microscopic Images before and after PCB Chemical Modification.Finally,the core-shell structural model of PCB and the PCB modified asphalt blending theory based on the nano-modified asphalt mechanism were proposed.Then the high and low temperature performance and storage stability of five kinds of modified asphalts including matrix asphalt,PCB modified asphalt,coupled PCB modified asphalt,SBS modified asphalt,and SBS-PCB composite modified asphalt were evaluated by conventional asphalt tests.SHRP performance test was used to grade PG of several modified asphalts with different contents and determine the optimum dosage and construction temperature.Finally,the road performance test was used to verify the high and low temperature performance and water stability of modified asphalt mixture before and after PCB chemical modification.Through the above study,we can see:The PCB has a particle size of about 3um and is concentrated between 200?1159nm,there is a large amount of ash(?-ZnS)on the surface,the presence of ash makes it less dispersible in asphalt and can easily cause segregation;the successful grafting of-CH(CH3)2 at IR at 1385 cm-1 indicates successful modification,the chemically modified PCB ash reduces the surface to be relatively smooth,and the particle size is significantly reduced,concentrated in the range of 15 to 398 nm,and its dispersibility and storage stability are improved;the IR diagram at 781.55cm-1 characterizes the aromatic substitution reaction,and its absorption peak becomes more significant with the increase of the content,but XRD indicates that the blending with the asphalt does not change the original interlayer distance,that is PCB and coupled carbon black react in asphalt by chemical blending and network filling mechanism;the penetration and softening point results indicate that the temperature and high temperature performance of the two modified asphalts increase significantly with the increase in PCB loading,the ductility results show that the low temperature performance has a certain decline,compared with the modified asphalt,the high temperature performance of the PCB modified asphalt is slightly lower,and the low temperature performance is improved,segregation tests show significant improvement in storage stability;however,the PG classification shows that except for the SBS-PCB compound modified asphalt,the grade is 76-22 when the amount is 25%;with the increasing of the PCB content,the PG classification of the modified asphalt of PCB and SBS-PCB is not changed;Road performance tests showed that the low temperature flexural tensile strength of PCB and coupled carbon black increased by 8%and 13%,respectively;road performance tests showed that the low-temperature flexural strength of PCB and coupled carbon black increased by 8%and 13%,and the dynamic stability increased by 57%and 54%,respectively.