Bitumen Emulsion Process

For the development of each nation, road network plays a very important role. Developed nation pays the cost of the effect of environmental conditions which is very harmful for human aspects. That’s why, there is great need for sustainable development for the preservation of environmental conditions. Many countries, including India, introduced Bitumen is used as a binder constituent in road construction. For reducing pollution and the heating effect, cold mix technology (type of bitumen) is used.

In cold mix technology, bitumen are used to aggregate in the road making process is in the form of a so-called “bitumen emulsion”. It is an emulsion liquid product of water and bitumen in which bitumen fine droplets are suspended in aqueous solution. Bitumen is a by-product of petroleum and it does not mix with water, so we are adding an emulsifier with water after that bitumen is added.

The Wahal bitumen emulsion colloid mill
is renowned for its ability to achieve a
droplet size of 0.5 microns and a fine and stable emulsion.
This is due to its multiple stages of rotors and stators,
which cause shear multiple times in a single pass.

The emulsifier is breaking down the bitumen into minute particles and keeps its suspension. Bitumen emulsion liquid consisting 3 things, i.e, water, emulsion and bitumen.

How is it manufactured?

There are two steps of emulsification of bitumen emulsion i.e.,

1. Emulsifier and other chemically active agents (like, HCl, CaCl2, etc.) are mixed with water in appropriate proportions depending upon the recipe. This is called soap solution 50 degree Celsius .It will be depends upon the ionic nature of the mix. In India, mostly, cationic type emulsions are used.

2. Now, the addition of bitumen 150 degrees with soap solution. the bitumen into minute particles and keeps its suspension. Bitumen emulsion liquid consisting 3 things, i.e, water, emulsion and bitumen.

3. It is done in a high shear mixer or homogenizer. It will be depends upon the use of bitumen emulsion, how much amount of bitumen is to be added to water. The average range of the ratio is from 40% to 70%. If work is so important then range must be high from 60% to 70%.

By the colloidal mill, bitumen breaks down into very tiny droplet upto 0.5 microns. Then, an emulsifier is added to create a coating of surface around of each and every droplet of the bitumen and it is also helping to keep the droplet is in dispersed and suspended form. Mix product is collected from the colloidal mill and stored in a storage tank for required use.

Types of Bitumen Emulsion

The two types of bitumen emulsion is that:

  1. Setting time:

In bitumen emulsion, bitumen is separated from water due to water evaporation. Bitumen acts as a binding material and spreads on the aggregate surface, which attains its strength very slowly. Bitumen particle separation from water depends upon the speed of water evaporation.

It is classified into three types :

  •  Slow Setting Emulsion : This process is used to de-escalate the water evaporation. It is very stable emulsifier.
  •  Medium Setting Emulsion : In this process, when applied the emulsion on aggregate, it doesn’t break. When the fine dust particles are spread over an aggregate then it escalates the evaporation process.
  •  Rapid Setting Emulsion : Emulsion can break down rapidly, when comes in contact with the aggregate and helping in fast setting and rapid cutting.
  1. Surface Charge:

They are divided into 2 types:

  •  Anionic Bitumen Emulsion : Anionic emulsion depends on the present water content. When water is evaporated by the electro negative charge aggregates, then it breaks the entire emulsion. If aggregates are wet, then it will delay and even prevent breaking. This type emulsion is favorable in rainy season only.
  • Cationic Bitumen Emulsion :  Cationic emulsion unlike anionic emulsion do not break due to water loss. In this emulsion electropositive particles and electronegative aggregates are attached by the strong ionic bond of respective polar charges. This type of emulsion is mostly used in many countries including India.

           Advantages of Bitumen Emulsion:

  1.  Emulsions can be used in wet weather.
  2. Soil stabilization in desert areas.
  3. Pavement of road surfaces.
  4. Premixing of bitumen emulsion and coarse aggregate.
  5. For uniform mixing of fine aggregates with bitumen.