In the road construction industry, bitumen emulsion is used more often than bitumen. This cohesive material was invented in the USA and it has been used for over half a century all over the world as one of the chief components of modern road construction materials.
Bitumen emulsion serves as the cohesive material for the tack coat. The physical characteristics of bitumen emulsion are as follows:
- dark;
- sticky;
- smelly; and
- hard when dry.
Substance Matter; this part does not need to be heated before being used, and it is capable of being distributed on the whole aggregate surface in a layer that is smoother than the bitumen itself. The cost of bitumen emulsion depends directly on the raw materials used in making the emulsion. In the road construction industry, bitumen emulsion is also used for asphalt coating under conditions of high humidity and low temperature. Moreover, it is also used for repairing potholes based on modern filling techniques such as cold working (when road repair operations are being performed), road surface treatment, and so on.
Bitumen emulsion is convenient in the servicing of road surfaces with multiple layers of paving materials. During the processing, this cohesive material is used for texture and structural renovation of the multiple layers, prevention of premature road failure, and for protection and resistence against water. Additionally, it provides better tire traction and reduces long term surface wear. Overall, using modern bitumen emulsion gives the road surface excellent performance characteristics and increases the service life of the roadway.
Bitumen emulsion consists of bitumen and water in the ratio of 50% bitumen and 40% water. Other products, such as cotton seed, sodium hydroxide and potassim make up the reaming 10% of the finished emulsion product.
There are two steps in the manufacturing of bitumen emulsion; (1) the bitumen stage; and (2) the water stage.
The bitumen stage can be described as the blending of bitumen with different additives known as firestarters. The water stage is the adding of emulsifiers to the water that is prepared for making the emulsion. The water stage includes the production of the emulsifier from the part of a pomade mixture. The pomade mixture consists of the after-product of cotton seed and flotogudron. In this part of the process, these two components are blended in the water with a warm solution of sodium hydroxide or potassium hydroxide until the entire mixture becomes disolved.
At this stage of the process, these two components are placed inside the special plant for blending. The unit is equipped with a colloid mill with rotating velocity of 6,000 turns per minute (6000 RPM). As a result, the bitumen is reduced to tiny micro particles measured in microns. These tiny particles form bubbles of emulsion water and are placed in a state of suspension within the liquid. The final product of this blending process is called “Bitumen Emulsion.”
The main advantage of this emulsion is in the reduction of the amount of resources and power required to create the final product. The operating costs are reduced, owing to the increased service life of bitumen emulsion under all extreme weather conditions from Spring through late Autumn. Moreover, the technology of using bitumen emulsion in road construction is very eco-friendly. There is no discharge from solvents into the air, and the explosion hazard, during processing and transporting of bitumen solvent, has been eliminated.
Bitumen emulsion increases the resilience, durability, and adhesive characteristics of the road surface coat. It also decreases the road surface’s sensitivity to fluctuations in temperature. Bitumen emulsion therefore, is one of the highest quality products of the modern chemical industry.