Materials which are being used for bond between different constituents of pavement, and that bond remains intact under different conditions. Binding materials actually increase the resistance between individual elements of mixture and increase its strength against impact loading.
There are different binding materials that are used for the construction of highways;
Emulsion is a binding material used for the construction of different types of highways depending on the requirements of highways. It is a mixture of asphalt cement, water, and different emulsifying agent. In the mixture of emulsion, water and cement exists in two different separate phases.
Binding Process Of Emulsion
For mixing with other materials an emulsifying agent is added. After addition, that emulsifying agent form a thin layer around the asphalt cement and that layer resist them from forming individual bond.
Now when this emulsion is used somewhere, than the layer that was form on the asphalt cement during mixing is now breakup and the water will evaporate. Now when this water evaporates a strong bond is formed between asphalt cement and emulsifying agent which goes on harden with the passage of time.
Benefits Of Emulsion
Purpose of emulsion includes different perspective, but mostly it is used for the very first coat of top layer of the road/highways, it is also used for the treatment of cracks. Emulsion can also be used under cold temperature, that’s the reason at worst conditions emulsion is the best suitable binding material.
Types of Emulsion
There are three types of emulsion depending on the charge present.
- Anionic emulsions
- Cat-ionic emulsions
- Non-ionic emulsions
- Anionic emulsion is the one in which there is a negative charged on the droplet. Droplet that is present on the asphalt.
- Cat-ionic emulsion is the one in which there is a positive charge on the droplet. Cationic emulsions are even best suitable for wet aggregates. These are best suitable for colder regions where freeze-thaw effect is prominent.
In cat-ionic emulsion, there are three types of setting;
- Cat-ionic rapid setting
- Cat-ionic Medium setting
- Cat-ionic slow setting
Non-ionic emulsions have no charge on it. These have some separate important function.