Bitumen emulsion is a liquid product in which bitumen is suspended in an aqueous medium in a finely divided state and stabilised by appropriate material. In India, cationic emulsions are commonly used. The amount of bitumen in the emulsion is around 60%, with the rest being water.
Bitumen emulsions are commonly used in pavement preservation techniques like chip seal, fog seal, and microsurfacing, which aim to preserve the road’s surface properties while preserving the structural layers beneath.
Process of production
The production of Bitumen emulsion in road construction is divided into two stages: first, the preparation of the water phase, and then emulsion production. The water phase is made up of water, emulsifier, acid (or alkali), and other additives in a special tank. The mixture has been thoroughly mixed. The pre-mixed water phase is injected into the bitumen when the emulsion is created.
The batch process uses a small number of components and can be manually controlled. The precision of component dosage determines the emulsion’s quality. As a result, the process must be automated. The need for a closed dosage system is dictated by the chemicals’ environmental and health risks.
The continuous process entails heating water and continuously dosing all components with a separate pump for each component. There is no need for consumption tanks. Apart from acid, which is dosed based on the indications of the water phase pH metre, this process requires automation with precise material dosage control.
Basic Knowledge
Bitumen is atomized into microscopic particles that are prone to coalescing during emulsification. To reduce the size of bitumen particles and prevent their coalescence after dispersion, a good emulsion requires the correct application of mechanical energy.
The colloid mill, the duration of the component’s presence in the mill, the concentration and type of emulsifier, and the emulsification temperature all influence particle size. During emulsification, the viscosity of bitumen should not exceed 500 cSt. Bitumen must be heated before entering the mill if this parameter is not met.
The water phase can also be heated to 30-70oC for a better surfactant solution. The hydrophilic nature of the surfactant determines the exact process of emulsifier stabilization. Coagulation of bitumen particles can be avoided if the emulsifier has a large hydrophilic group.
So, that is all for basic knowledge about Bitumen emulsion in road construction and the process in which it is used.
Bitumen is now primarily used in the road construction and maintenance industry. Bitumen emulsions are a bitumen dispersion in an aqueous continuous phase that has been stabilized with the addition of an emulsifier. At high temperatures, they are prepared as Bitumen emulsion in road construction, but at room temperature, they are applied as solid dispersions. Bedrock Bitumen emulsions are commonly used in road construction in conjunction with mineral aggregate.
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