![]() ![]() ![]() The process is simple, economical, operable, and relatively stable product quality. Qualified asphalt products can be produced by reasonably selecting soft and hard blending components. ④ The blending process is the most commonly used method for producing road asphalt. ③ The oxidation process increases the softening point and reduces the penetration of asphalt by the complex oxidation reaction, but it also produces many environmentally harmful by-products.The oxidation process is considered when the deep distillation drawing process cannot meet the requirements. The solvent deasphalting process is flexible in dealing with different crude oil and designing hard asphalt with different penetration degrees. This process aims to produce more high-quality deep-processed raw materials and blending components to improve the economic efficiency of the producer. The remaining higher polar aromatics and asphaltenes can be used as the blending component of asphalt. It selectively extracts saturated hydrocarbons and less polar aromatics in the residual oil. ② The solvent deasphalting process uses light hydrocarbons (propane, butane, pentane, or their mixtures) as solvents. However, limited by the distillation device cutting range, it is possible to produce good hard asphalt products when the raw material is heavy or medium crude oil. The distillation cutting temperature is required to be relatively high in the process of hard asphalt. However, the properties of the produced asphalt rely on the quality of crude oil. ① The distillation process is the most convenient and economical route for the production of road asphalt. The manufacturing processing techniques of hard asphalt include the distillation method, oxidation method, solvent deasphalting method, and blending method. Hard asphalt could be directly produced from petroleum refining by changing the conditions and basic processes and does not require expensive additives or complex construction processes. The binder used in the high modulus asphalt mixture (NFP98-140/141) is an exceptional hard-grade paving asphalt with a penetration degree of 10–20 (0.1 mm) and 15–25 (0.1 mm) at 25 ☌, also called the hard asphalt. Advantages of high modules asphalt include excellent rutting resistance and fatigue resistance, which enhances the high-temperature rutting resistance and prevents early distress showing the significant potential social and economic benefits. This kind of high-modulus asphalt mixture in France is called Enrobésà Module Elevé and Béton Bitumineuxà Module Elevé. To overcome the challenge of the European energy crisis in pavement construction, the high-modulus asphalt mixture was proposed by French pavement researchers, which reduces the quantity of the usage asphalt in pavement, maintain the road performance, and reduces the thickness of the pavement structure. The viscous behavior of asphalt cannot be directly characterized by microstructural distribution but requires further attention to the intermolecular forces within the microstructure. The variation coefficient shows that the saturates components have more significant aggregation behavior than the asphaltenes component. The variation coefficient of the density map follows the same trend as the CII values when characterizing the dispersion ability of the resins and aromatics components. Short, unordered planar accumulations dominate the asphalt microstructure. Meanwhile, the aromatics component and the number of branches connected to the aromatics rings in the molecular system are closely related to the low-temperature performance. ![]() The results indicated that the resins component and the number of saturated carbon in the molecular structure are closely related to the high-temperature performance. Systemic molecular dynamics were applied to reveal the microstructure characteristics by producing the density map and the mean square Displacement. To better design and application of hard asphalt, the conventional properties tests, SARA composition experiments, 1H NMR experiments, and elemental analysis were carried out for five types of hard asphalt and three types of virgin asphalt, and correlation analysis was performed.
0 Comments
Leave a Reply. |