Bitumin Emulsion

Bitumen emulsion is a mixture of fine droplets of bitumen and water. But as the bitumen is a petroleum product it doesn’t mix with water and as it is sticky in nature, it doesn’t easily gets disintegrated into fine droplets. To overcome this problem an emulsifier is used. Emulsifier can be defined as a surface-active agent. Emulsifier keeps the bitumen in its fine droplet state by disallowing it to mix with other droplets. As the droplets are very fine they suspend in water. “Therefore, bitumen emulsion is a dispersed liquid consisting of three products, i.e. water, bitumen and emulsion”.

The bitumen emulsion is classified into types based on Setting Time when the bitumen emulsion is applied on the aggregate for the road works the water evaporates leaving behind the bitumen droplets. These droplets spread on the aggregate and bind with each other and gains strength eventually. Based upon the time taken by the vitamin emulsion to evaporate the water and between particles to separate from water, bitumen emulsion is further classified into 3 types based on setting time:

a) Slow setting emulsion

In this type of emulsion, a special type of emulsifier is used to slow the process of water evaporation. These types of emulsifiers are relatively stable. Slow Setting Emulsion is further subdivided into SS-1 and SS-2 types.

b) Medium setting emulsion

This type of bitumen emulsion doesn’t break as when applied on aggregate. The process of evaporation starts when the fine dust of minerals is mixed with the aggregate emulsion mix.

c) Rapid setting emulsion

This type of bitumen emulsion breaks down rapidly as it comes with contact with aggregate helping in fast setting and rapid curing. Break is rapid even with coarse aggregate of relatively low surface area. Rapid Setting Emulsion is further subdivided into RS-1 and RS-2 types.