Study On The Mechanism Of Coal Tar Pitch Modified Petroleum Asphalt

Coal tar pitch(CTP) as the important byproduct of coal chemical industry has been applied to the field of electrode material and carbon fiber,but the field's consumption is small. So efficient application of CTP has always been a research hotspot. Technology reports in recent years showed that the mixture material of petroleum asphalt and CTP could be applied to high-grade highway construction as paving materials. Although previous studies have analyzed the performance of the mixed asphalt,the interaction mechanism of petroleum asphalt and CTP has not been discussed thoroughly. The regular performance of modified petroleum asphalt have been studied and different methods have been used to explore the mechanism of them in this paper,which can provide a technical basis for promotion of CTP as petroleum asphalt modifier in entity project.The technological parameters such as CTP's types,proportion,particle size and stirring methods have been studied in this paper. Preparation of modified asphalt with two kinds of medium temperature CTPs is done in a 0.5L reactor. CTPs were selected from Xuyang Chemical Company and Taiyuan Chemical industry Group Co. And the modified effect of CTP's component on petroleum asphalt has been investigated. The results show technological parameters that mentioned above have certain regular impact on capability of mixed asphalt. Modified effects of petroleum asphalt differ with component of CTP. The softening point and anti-aging property of base asphalt have been improved effectively through adding CTP. And the component of CTP which has best modified effect on base asphalt is THFS(Tetrahydrofuran Solubles), which can not only enhance softening point of base asphalt but also remain its ductility well.In order to explore interaction between CTP and base asphalt, methods of simple calculation, four component analysis and HPLC have been adopted in this paper to discuss the change among components of mixed asphalt. The result show that chemical changes occur when mix CTP and petroleum asphalt. The function of chemical change can not be ignored though it is relatively weak. About 10 percent light component of them turn to be mid-quality component by “polymerizing” and about 4.5 percent heavy component turn to be mid-quality component by “dissolving” after mixing of CTP and petroleum asphalt. Finally mixed asphalt forms a stable colloidal structure.