BITUMEN EMULSION – WHAT, WHY & HOW?

Definition – What is bitumen emulsion?

Bitumen Emulsion - What, Why and How
Bitumen Emulsion – What, Why and How

Bitumen emulsion is a mixture of water and bitumen. Hey wait, we know that bitumen is an oil product and cannot be mixed with water. So we mix an emulsifier (a surface active agent) with water before adding the bitumen. Mixing the emulsifier with water helps break down the bitumen into fine particles and disperse it in suspension.


Hence we can say that bitumen emulsion is a liquid product consisting of three things, (ie.) water + emulsion + bitumen) where droplets of bitumen are suspended in water.

production – How is it made?

There are two primary steps in the production of bitumen emulsion.

1. Inscheduled tribe Step water is mixed with suitable emulsifying agent and other chemicals. The type of emulsifier used depends on the ionic nature of the mixture.

2Ra is the sum of steps asphalt With water-emulsifying mixture, This is done in a colloidal mill. depending on usage, amount of bitumen Mixing with water may limit 40 to 70%. The water-emulsifying mixture and bitumen is pumped into a colloidal mill, The colloidal mill breaks the bitumen into smaller droplets. mean diameter Of these small drops of bitumen, approximately 2 microns, here comes the role of emulsifier, The emulsifier creates a coating of surface charge around the droplets of bitumen which helps to keep these tiny particles away from each other. It also helps to keep these particles in a dispersed form.

2 . after the completion ofRa Step, the bitumen emulsion is pumped into the storage tank.

classification – How to classify bitumen emulsion?

There are two different ways to classify bitumen emulsion, as detailed below.

  1. based on surface charge
  2. based on timing

based on surface charge

Based on the type of surface charge, bitumen emulsions are mainly classified into the following two types.

  1. ionic bitumen emulsion
  2. cationic bitumen emulsion

in the case of one ionic bitumen emulsion, bitumen particles are electro-negative charge, where as for cat-ionic emulsion, bitumen particles are electro-positive charge, Cationic bitumen emulsions are most commonly used nowadays.

The choice of bitumen emulsion (ie ionic or cationic) to be used depends on the mineral composition of the aggregate used for manufacture. In the case of silica-rich aggregates, the surface of the aggregate is electro-negatively charged. Therefore, cationic emulsions should be used. This will help in better diffusion and binding of the bitumen with the aggregate.


depending on setting time

When bitumen emulsion is applied to the aggregate, the water evaporates, separating the bitumen from the water. And then the bitumen spreads on the surface of the aggregate and acts as a bonding material and gradually gains its strength.

Water is classified into the following 3 types on the basis of the speed at which it evaporates and the bitumen particles separate from the water.

  1. Rapid setting emulsion (Rupees,
  2. medium setting emulsion (M / s,
  3. slow setting emulsion (SS,

pay attention, word here”Establishment“should not mean the attainment of power; Rather it means the time taken by the bitumen to separate from the water.

In the case of rapidly setting emulsions, bitumen is intended to break down rapidly. Therefore this type of emulsion quickly solidifies and cures.

Medium setting emulsions do not break spontaneously when applied over aggregates. But the process of breakdown begins when the fine dust of minerals is mixed with aggregate-emulsion mixture,

Slow setting emulsions are manufactured using special types of emulsifiers, making the setting process very slow. These types of emulsions are relatively stable.

Factors affecting setting of emulsion

The following factors affect the setting and curing of bitumen emulsion mix.

  • water absorption of aggregates
  • surface texture of aggregate
  • Overall amount of mineral dust
  • gross upgrade
  • mineral composition of the aggregate
  • Total surface charge intensity
  • The type of emulsifier used and its quantity
  • atmospheric conditions, climatic conditions
  • wind speed and height
  • Drainage conditions at construction site

Application – What are the uses of bitumen emulsion?

  1. The emulsion is used in bituminous road construction work. They are especially helpful for maintenance and patch repair tasks.
  2. The emulsion can be used in wet weather even when it rains.
  3. Also emulsions have been used in soil stabilization, particularly for sand stabilization in desert areas.
  4. A rapid setting type emulsion suitable for surface dressing and admixture macadam type formulations.
  5. The medium setting type is used for premixing with coarse aggregates.
  6. In the case of fine aggregates, the surface area of ​​the aggregate is greater and the resulting emulsion requires a longer period of time to mix. Hence slow setting emulsion is preferred which gives sufficient time for uniform mixing of the mixture.

What are the benefits and limitations of bitumen emulsion?

Benefits – Why Use Bitumen Emulsion?


  • The strength properties of bitumen are preserved in emulsion mixes because the emulsion does not require hot mixing. Generally cold mixing or emulsion mix is ​​used for the manufacture of pavement by slightly heating the material.
  • The emulsion can be used in wet weather even when it rains.
  • The emulsion has anti-striping properties.
  • Low viscosity or thin consistency emulsions improve dispersion ability and allow better coating of bitumen on the surface of the aggregate.
  • There is no wastage during laying and storage.
  • Since emulsions are water based, their impact on the environment is minimal.
  • It is the least energy intensive of all building materials: there is no need for heat.

limits

  • No one type of emulsion is suitable for every task. It depends on whether the aggregate is acidic or basic in nature.
  • Setting time may vary depending on air temperature, wind velocity and type of emulsion.
  • There is a wide range of cure times; A suitable emulsion mix needs to be designed for a particular requirement, i.e. we need to determine the optimum quantity of emulsion for each case, based on area, type of emulsion, mix grade and desired mechanical properties.
  • Its storage time is limited (from a few days to six months)

Er. Mukesh Kumar

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Er. Mukesh Kumar is Editor in Chief and Co-Funder at ProCivilEngineer.com Civil Engineering Website. Mukesh Kumar is a Bachelor in Civil Engineering From MIT. He has work experience in Highway Construction, Bridge Construction, Railway Steel Girder work, Under box culvert construction, Retaining wall construction. He was a lecturer in a Engineering college for more than 6 years.