Bitumen Modified and Emulsified DeviceEmulsified asphalt production process
- According to the scale of production, specific production conditions and process requirements, emulsion preparation methods are various forms. The typical emulsion preparation is based on water, and emulsifier, stabilizer and acid must be added as the proportion of the design; a variety of additives is dissolved in water together, and when the dissolved solution is run out, the production is necessary to idle time, this is a intermittent production process, which applies to small-scale production. For the maintenance of continuous production, the dissolution tank must be two or more for alternate preparation of emulsifier solution.
- A variety of emulsifiers and stabilizers is dissolved in water at different speeds, thus, in order to improve the dissolution efficiency, these additives can be dissolved in different tank. Moreover, it is easy for the workers to increase water temperature, improve the mixing intensity, and then blend solution as the proportion.
- As the emulsification process of emulsion used is in lower temperature, while emulsifier dissolved needs a higher temperature to facilitate dissolution fully. Therefore, in the larger scale of production， the additives should be dissolved firstly ,and then emulsion is finished under the lower temperature water .
Modified emulsified asphalt production process
- The modified emulsified asphalt means asphalt is emulsified firstly, and then is modified; or is modified and emulsified at the same time. The modified asphalt emulsion, its characteristics are the modifier used must be liquid; production process is simple, the emulsifier must be added into the emulsified asphalt as the proportion to mix; or the emulsifier must be added into emulsion as the proportion to emulsify asphalt. And, modified emulsified asphalt is going to be finished.
Emulsified modified bitumen production process
- The so-called modified bitumen emulsion is firstly modified, and then is emulsified. Technology line of modified emulsified asphalt has three forms, as follow:
- 1. Using latex as modifier. This form costs energy consumption and gets complicated application procedures very difficultly; moreover, it is quite hard to disperse the modified asphalt in emulsion, so it has not been used.
- 2. Using solid-state modifier. This form of multi-process procedures, high cost, production and insecurity and environmental pollution, are now rarely used.
- 3, Using solid thermoplastic elastomeric material (such as SBS).The material and the melting asphalt mixed together ,through the mechanical dispersion, the modified bitumen are going to be finished , and then the modified bitumen is dispersed in the emulsion preparation to reach emulsifying. This form of technology has two major challenges:
- Firstly, the modifier must be crushed into fine particles. In the emulsified modified bitumen, the dispersed phase particle diameter of the modified asphalt should be 5-6um below, otherwise the emulsion will not be stable, while the modifier is being surrounded by asphalt composition, the modifier particle size must be much smaller, yet it is also very difficult to crush SBS with a machine.
- Secondly, very difficult to disperse modified asphalt in the emulsion. Asphalt is modified by SBS, whose viscosity is increased. Once it is mixed with the emulsion, the heat in the modified asphalt is being transferred into the emulsion rapidly, the temperature falls down quickly, the viscosity is rapidly being raised, and it is more difficult to disperse. However, this way of production of modified emulsion asphalt has excellent technology and economics and bright future.
