Asphalt Production Methods

Asphalt Production Methods.
(1) distillation method: is the regular pressure distillation of crude oil from gasoline, kerosene, diesel and other light fractions, and then by decompression distillation (residual pressure of 10 ~ 100mmHg) out of the decompression distillate oil, the remaining residue in line with the specifications of road asphalt can be produced directly out of the asphalt products, the resulting asphalt is also known as straight-run asphalt, the production of road asphalt is the main method of asphalt.
(2) solvent precipitation: non-polar low molecular alkane solvent on the decompression of the components in the residual oil has a different solubility, the use of solubility differences can be realized component separation, and thus can be removed from the decompression of the residual oil on the asphalt properties of the components are not conducive to the production of asphalt products to meet the specifications of the requirements of the solvent precipitation method.
(3) oxidation method: is in a certain range of high temperature to decompression slag oil or de-oiled asphalt blown into the air, so that its composition and performance changes, the resulting product is called oxidized asphalt. Decompression slag oil at high temperatures and blowing air will produce vaporization and evaporation, while dehydrogenation, oxidation, polymerization and condensation and a series of reactions. This is a multi-component interaction of a very complex integrated reaction process, rather than just an oxidation reaction, but customarily known as the oxidation method and oxidized asphalt, also known as air blowing method and air blowing asphalt.
(4) blending method: blending method for the production of asphalt initially refers to the same crude oil constitutes the asphalt of the four components according to the quality requirements of the required proportion of re-blending, the resulting product is called synthetic asphalt or reconstruction of asphalt. With the development of process technology, the source of blending components have been expanded. For example, from the same crude oil or different crude oil residues or components of primary and secondary processing, as well as a variety of industrial waste oil as a blending component, which reduces the dependence on the choice of oil sources in the production of asphalt. With the growing shortage of crude oil suitable for the manufacture of asphalt, blending law shows the flexibility and economy is increasingly being emphasized and commonly used.
(5) emulsification method: asphalt and water surface tension difference is very large, at room temperature or high temperature are not miscible with each other. But when the asphalt by high-speed centrifugation, shear, from the mechanical action, so that it becomes a particle size of 0.1 ~ 5 microns of particles, and dispersed into the water medium containing surfactants (emulsifiers - stabilizers), due to the emulsifier can be directed to adsorb on the surface of the asphalt particles, and thus reduces the interfacial tension of the water and asphalt, so that the asphalt particles can form a stable dispersion system in water, so that the asphalt particles can be used in the water. Water to form a stable dispersion system, which is the oil-in-water emulsion. This dispersion system was tea brown, asphalt for the dispersed phase, water for the continuous phase, at room temperature with good mobility. In a sense, emulsified asphalt is water to "dilute" asphalt, thus improving the fluidity of asphalt.
(6) modified asphalt: modern highways and roads have undergone many changes: traffic flow and driving frequency has increased dramatically, the axle weight of freight cars continue to increase, the general implementation of one-way traffic lane, the requirements to further improve the pavement resistance to mobility, that is, high temperature rutting resistance; improve flexibility and elasticity, that is, low-temperature resistance to cracking ability; improve the wear-resistant ability and prolong the service life. Modern buildings commonly use large-span prestressed roof panels, requiring roof waterproofing materials to adapt to large displacements, more resistant to severe high and low temperature climate conditions, better durability, self-adhesive, easy to construct, and reduce maintenance workload. These changes in the use of the environment pose a serious challenge to the performance of petroleum asphalt. Modification of petroleum asphalt to make it adapt to the above demanding requirements, has attracted attention. After decades of research and development, there have been many varieties of modified road asphalt, waterproofing membranes and coatings, showing a certain degree of engineering effectiveness. However, in view of the modified material prices are usually 2 to 7 times higher than ordinary petroleum asphalt, the user has not been able to fully grasp the engineering performance of the material, modified asphalt production growth is slow. Currently modified road asphalt is mainly used for airport runways, waterproof bridge decks, parking lots, sports stadiums, heavy traffic surfaces, intersections and road curves and other special occasions of paving applications. Recently, Europe will be modified asphalt applied to the maintenance and reinforcement of the highway network, a greater impetus to the general application of modified road asphalt. Modified asphalt waterproofing membranes and coatings are mainly used for high-grade waterproofing projects. With the progress of science and technology and the development of economic construction, will further promote the development of varieties of modified asphalt and the development of production technology. Modified asphalt varieties and preparation technology depends on the type of modifier, the amount of modifier and matrix asphalt (i.e., raw asphalt ) composition and nature. As a result of the many varieties of modifiers, different forms, in order to make it with petroleum asphalt to form a homogeneous material available for engineering purposes, over the years to evaluate the various types of modifiers, and develop the corresponding formulations and methods of preparation, but most of the modified asphalt has been practical engineering belongs to the patented technology and patented products.