Nowadays, asphalt pavement is widely used in road construction due to its many advantages. At present, we mainly use hot bitumen and emulsified bitumen in the construction of asphalt pavement. Hot bitumen consumes a lot of heat energy, especially large quantities of sand and gravel materials that require baking heat. The construction environment for operators is poor and the labor intensity is high. When using emulsified bitumen for construction, heating is not required and it can be sprayed or mixed for paving at room temperature, and pavement of various structures can be paved. Moreover, emulsified bitumen can flow by itself at room temperature, and can be made into emulsified bitumen of different concentrations as needed. It is easy to achieve the required asphalt film thickness by pouring or permeating the layer, which cannot be achieved by hot bitumen. With the gradual improvement of the road network and the upgrading requirements of low-grade roads, the use of emulsified bitumen will become larger and larger; with the enhancement of environmental awareness and the gradual shortage of energy, the proportion of emulsified bitumen in asphalt will become higher and higher. The scope of use will also become wider and wider, and the quality will become better and better. Emulsified bitumen has the characteristics of non-toxic, odorless, non-flammable, fast drying and strong bonding. It can not only improve road quality, expand the scope of asphalt use, extend the construction season, reduce environmental pollution and improve construction conditions, but also save energy and materials. 

Emulsified bitumen is mainly composed of bitumen, emulsifier, stabilizer and water.
1. Bitumen is the main material of emulsified bitumen. The quality of asphalt is directly related to the performance of emulsified asphalt.
2. Emulsifier is a key material in the formation of emulsified asphalt, which determines the quality of emulsified asphalt.
3. The stabilizer can make the emulsified asphalt have good storage stability during the construction process.
4. It is generally required that the water quality should not be too hard and should not contain other impurities. The pH value of the water and calcium and magnesium plasma have an impact on emulsification.
Depending on the materials and emulsifiers used, the performance and use of emulsified asphalt are also different. Commonly used ones are: ordinary emulsified asphalt, SBS modified emulsified asphalt, SBR modified emulsified asphalt, extra slow cracking emulsified asphalt, high permeability emulsified asphalt, high concentration High viscosity emulsified asphalt. In the construction and maintenance of asphalt pavement, suitable emulsified asphalt can be selected according to road conditions and properties.