Research On The Influence Of Crude Oil On The Low-penetration-grade Asphalt And Pavement Performance

Road asphalt are mianly derived from petroleum asphalt, and asphalt is a byproduct of petroleum. The property of crude oil and refining process have great influence on the pavement performance of asphalt. It is significant to choose appropriate crude oil and refining process for producing high-quality road asphalt that can satisfy the requirement of pavement performance.Compared with the wide application of 70# asphalt in C hina, for the short time of the manufacture and application of the asphalt of low penetration, it selected the proper manufacture technology for the asphalt of low mark number by comparison and ana lysis in this paper. In the condition of the fixed technology, it selected three kinds of crude oils(mark B, M, R) imported from abroad as suitable for prepare the petroleum asphalts for road pavement, to prepare 3 kinds of 30# asphalt and 50# asphalt respectively, and to make sure the basically same penetration of the asphalt of the same mark number at 25°C. By the analysis system of the penetration in C hina and the study of the rheology of the properties of the asphalts, it evaluated the properties of high temperature, low temperature and thermosensitivity of the 6 kinds of prepared asphalts of the low mark number, and established the relationship of the properties between the asphalt and crude oil. It also designed a kind of AC-20 mixture to prepared the asphalts by the 6 kinds of hard asphalts, whose pavement performance of the high temperature, low temperature, fatigue and water stability were evaluated, to establish the corresponding relationship between the properties of the crude oil and the pavement performance of the asphalt mixture. Based on the above researches, it selected the optimum type of the crude oil to manufacture the petroleum asphalts for road pavement.The research shows that: the high-temperature behavior of the 30# asphalt is better than the 50# asphalt. For the low-penetration asphalt of the same mark prepared by different crude oil, whose high-temperature performance is in accordance with its asphalt mixture, and is also consistent with the carbon residue value in the crude oil, as is well known that the higher carbon residue value, the better high-temperature performance. For the asphalt of the same mark, the PI values are in accordance with the variation rates of the rutting factors. When the variation rates of the viscosity of the residual oil and the crude oil become faster, the higher the PI values present, as the faster of the variation rates of the rutting factors. By evaluating the low-temperature performance of the asphalts, there are minor differences between the asphalts and its mixtures,that’s to say,types of crude oil have little impact on the low-temperature performance of the asphalts. As the low-temperature performance of the hard asphalt is poorer than the normal asphalt(70#), such properties as the ductility is low, so it is suggested to raise the evaluating temperature of the low-temperature performance of the hard asphalt properly. The water stability of all prepared hard asphalt mixtures can meet the requirements in the humid area, with minor differences, it is conc luded that the influence of the types of crude oil on the water stability are negligible. The results of the semi-circular fatigue tests show that, there are significant influences of the asphalt marks on the fatigue properties of the asphalt. The smaller of the asphalt mark nu Ber is, the poorer fatigue property presents, while there are no obvious influence of the types of the crude oil on the fatigue properties of the asphalt mixtures.