1. Penetration
The depth to which a standard needle with a certain mass attached vertically penetrates the asphalt sample vertically at the specified temperature and time is expressed in 0.1mm.
2. Ductility
The length of an asphalt sample of a specified shape when stretched to break at a certain speed at a specified temperature, expressed in cm.
3. Softening point
The asphalt sample is placed in a metal ring of specified size, with a metal steel ball of specified size and mass placed on it, and placed in water or glycerin. Heating at a high speed until the steel ball sinks to a specified distance, the temperature is expressed in °C.
Extended information
Production method
1. Distillation method
It is to distill crude oil under normal pressure to separate gasoline, kerosene, diesel, etc. The light fraction is then subjected to vacuum distillation (residual pressure 10~100mmHg) to separate the vacuum distillate. When the remaining residue meets the specifications of road asphalt, asphalt products can be directly produced. The resulting asphalt is also called straight-run asphalt, which is used for road production. The main method of asphalt.
2. Solvent precipitation
Non-polar low-molecular-weight alkane solvents have different solubilities for each component in vacuum residue oil. The difference in solubility can be used to achieve component separation. , thus the components that are detrimental to the properties of asphalt can be removed from the vacuum residue to produce asphalt products that meet the specifications. This is the solvent precipitation method.
3. Oxidation method
It blows air into the vacuum residue or deoiled asphalt at a certain range of high temperature to change its composition and properties. The resulting product is called It is oxidized asphalt. Vacuum residual oil will vaporize and evaporate under the action of high temperature and blowing air, and a series of reactions such as dehydrogenation, oxidation, polymerization and condensation will occur at the same time.
This is a very complex comprehensive reaction process in which multiple components interact with each other. It is not just an oxidation reaction, but it is customarily called oxidation method and oxidized asphalt. It is also called air blowing method and Air blown asphalt.
4. Blending method
The blending method to produce asphalt initially refers to the 4 components of asphalt composed of the same crude oil being re-blended in the proportion required by the quality requirements. The resulting product is called synthetic Asphalt or reconstructed asphalt. With the development of process technology, the sources of blending ingredients have expanded.
For example, the residues or components of primary and secondary processing of the same crude oil or different crude oils and various industrial waste oils can be used as blending components, which reduces the selection of oil sources in asphalt production. dependence. With the increasing shortage of crude oil suitable for making asphalt, the flexibility and economy shown by the blending method are increasingly being valued and widely used.
5. Emulsification method
The surface tensions of asphalt and water are very different, and they are not miscible with each other at normal or high temperatures.
However, when asphalt is subjected to mechanical actions such as high-speed centrifugation, shearing, and impact, it becomes particles with a particle size of 0.1~5 μm, and is dispersed into particles containing surfactants (emulsifiers-stabilizers). In water media, because the emulsifier can be directionally adsorbed on the surface of asphalt particles, it reduces the interfacial tension between water and asphalt, allowing the asphalt particles to form a stable dispersion system in water, which is an oil-in-water emulsion.
This dispersion system is brown in color, with asphalt as the dispersed phase and water as the continuous phase, and has good fluidity at room temperature. In a sense, emulsified asphalt "dilutes" the asphalt with water, thereby improving the fluidity of the asphalt.
6. Modified asphalt
Modern highways and roads have undergone many changes: traffic flow and driving frequency have increased dramatically, the axle load of freight trucks has continued to increase, and lane separation and one-way separation have been widely implemented. Driving, it is required to further improve the road's fluidity resistance, that is, its ability to resist rutting at high temperatures; improve flexibility and elasticity, that is, its ability to resist cracking at low temperatures; improve its wear resistance and extend its service life.
Modern buildings generally use large-span prestressed roof panels, which require roof waterproofing materials to adapt to large displacements, be more resistant to harsh high and low temperature climate conditions, have better durability, have self-adhesiveness, facilitate construction, and reduce Maintenance workload. These changes in the use environment have increased the performance requirements for petroleum asphalt. Modification of petroleum asphalt to adapt to the above-mentioned harsh usage requirements has attracted people's attention.
After decades of research and development, a wide variety of modified road asphalt, waterproofing membranes and coatings have emerged, showing certain engineering practical effects.
However, given that the price of modified asphalt is usually 2 to 7 times higher than that of ordinary petroleum asphalt, users have not yet fully grasped the engineering performance of the material, and the output of modified asphalt has grown slowly.
Modified road asphalt is mainly used for paving applications in special occasions such as airport runways, waterproof bridge decks, parking lots, sports fields, heavy traffic pavements, intersections and road turns. Recently, modified asphalt has been applied to the maintenance and reinforcement of road networks in Europe, which has greatly promoted the widespread application of modified road asphalt. Modified asphalt waterproofing membranes and coatings are mainly used in waterproofing projects for high-end buildings.
The variety and preparation technology of modified asphalt depend on the type and amount of modifier and the composition and properties of the base asphalt (i.e. raw asphalt).
Due to the wide variety of modifiers with different forms, in order to form a uniform material with petroleum asphalt that can be used for engineering applications, various types of modifiers have been evaluated over the years and corresponding ones have been developed. Formulas and preparation methods, but most of the modified asphalts that have been put into practical use are patented technologies and patented products.
Baidu Encyclopedia-Petroleum Asphalt