Study On Properties And High-temperature Storage Stability Of SBR-chemical Modification Asphalts

Polymer modified asphalts (PMA) are very important highway materials which are developing in recent more than 20 years, SBS\SBR polymer modified asphalts were applied on highways and airport roads with heavy traffic and special technology environments. Physical modified polymer asphalts were not satisfied with the needs of application, but chemical modified polymer asphalts were satisfied with the excellent binder elasticity at high temperature, and improved the binder flexibility at low temperature, the temperature susceptibility was also reduced. Because the polymers did not separate from asphalts, which having good properties at high depositing temperature.Polymer modified asphalts were prepared by blending asphalts and PSBR1500 made by Lanzhou Petrochemical Division of Petrochina, a series of experiments were investigated by chemical reaction modifications of polymer modified asphalts with vulcanization acceleraters and stabilizing agents as kaolinite clay, based on the opitimizing recipes and processing technology, SBR-reactive modified asphalts were developed in laboratory, which to satisfy with the standard JTG F40-2004 completely. The compatibility between base asphalts and modifiers had been improved, the storage stability of the modified asphalt under high temperature had been improved greatly, the disparity of softening point after storing under 163℃less than 2.2℃had been achieved. Experiments indicate that the modified asphalt would satisfy with the industrial application completely. The glass temperature of PMAs were below -35℃, the temperature of G*/sinδ=1000Pa was about 70℃, the binder elasticity at high temperature was greatly improved, and also improved the binder flexibility at low temperature, the temperature susceptibility was also reduced greatly.Polymer modified asphalts were prepared with SBR/some reactive vulcanized agents and kaolinite clay using a special mixing technique. The dynamic mechanical properties of SBR-modified asphalts before and after adding reactive vulcanized agents and KC were characterized by using dynamic shear rheometry. The addition of reactive vulcanized agents and kaolinite clay to SBR modified asphalts resulted in the formation of a chemically vulcanized SBR network structure in modified binders, and the low temperature abilities of the binders was greatly improved and their temperature susceptibility was reduced to a great extent, it was found that the addition of SBR increased the binder elasticity at low temperature and specially reactive modification was improved viscous property at high temperature. The structures and chemical properties were determined by IR,1H-NMR and 13C-NMR,element analysis,GPC and DSC, reactions between polymers and asphalts were verified. The morphology of SBR-modified asphalts, which was characterized by fluorenescence photomicrograph and SEM, showed that the compatibility and high-temperature storage stability of SBR-modified asphalts were improved by additions of reactive vulcanized agents and kaolinite clay.The mechanism of deposit at high temperature were discussed , because of the forming net structure between polymer and asphalts, the storage stability was greatly improved.Relations between components of asphalts and reaction levels were discussed, saturates didn't change in the process of modification, aromatics were decreased in the reactions, also resins took part in the process based on acids catalyzed reaction, stabilizers were activated in the reactions based on acids, penetrations were decreased, softening points , ductilities and toughnesses/tenacities of PMAs were increased with strengthing of the reaction, poly phos.acid Kc were useful for ductility at 5℃after TFOT.PMAs of the study were greatly improved the abilities of the base asphalts by the chemical mixing technique, some valuable modified compose system were selected from a lot of experiments results, which can be applied properly to different component asphalts. The improved techniques of asphalts in the thesis have special excellences which have no any pollution on the environments.