Different Types of Asphalt Binders - Bitumen Grades
In road construction and asphalting the streets, bitumen is mainly used as a binder in the road layers. In road construction, penetration grade bitumen and viscosity grade bitumen are the most commonly used grades; however, other types of bitumen can also be used.
According to the «different types of bitumen used for road construction» article by Infinity Galaxy, there are various grades of bitumen applied in road construction.
In addition, you can also read this article to learn more about different grades of bitumen in road construction.
A road is a combination of several layers including sub base course, base course and surface course. Sub base course is the bottom layer of a road, base course is a layer between sub base course and surface course. The surface course is the layer at the top that has a high resistance to forces entering from the top side.
What are the different types of bitumen that can be used in the surface course?
Asphalt is a mixing of different materials including different types of aggregates, bitumen binder and sometimes different additives that can improve its performance.
The exact use of bitumen is that these materials can bond the aggregates and make a firm asphalt. Hot asphalt, cold asphalt and protective asphalts are the main types of asphalts that bitumen can be used in each of them. Hot asphalt is a mixture of bitumen and aggregates that are heated in the factory. The below bitumen are using in this type of asphalt:
- Penetration Grade 60/70
- Penetration Grade 40/50
- Penetration Grade 80/100
- Penetration Grade 120/150
Cold asphalt is bitumen mixed with aggregates and is applied on the surface at ambient temperature. The bitumen used in this type of asphalt is different types of bitumen emulsion and cutback bitumen most of the time. Generally, it is better to use bitumen emulsion since it is a mixture of bitumen and water while the cut back bitumen is a mixture of bitumen and a petroleum based solvent.
Protective asphalt is usually used as a temporary coating in the road construction industry and is not one of the main components of the road body. This layer is mostly used to make the asphalt impermeable and prevent erosion of the main layer. Using it can strengthen the main layer of asphalt that is on the road.
Different types of protective asphalts are prime coat, tack coat, seal coat, slurry sealing, micro surfacing and chip sealing. In the below table, the types of bitumen that can be used in protective asphalts is shown:
Base course bitumen types
Generally speaking, three types of bitumen are used in the base course of roads as below:
Viscosity Grades Bitumen:
The viscosity grade of bitumen is determined by its viscosity after production at the refinery. It is a relatively new classification of bitumen.
Oxidized or Blown Bitumen:
By blowing hot air into penetration bitumen, oxidized bitumen is produced. This type of bitumen is chemically stable and has high durability.
Bitumen Penetration Grade:
Penetration grade bitumen is classified by penetration test. Bitumen penetration grades are used in the manufacture of hot mix asphalt for road bases. The table below shows different grades of this bitumen:
Infinity Galaxy has presented a complete report of each grades of bitumen that can be used in different layers in road construction that you can read on its website.