Bitumen emulsion is a liquid product in which bitumen is suspended in a finely divided condition in an aqueous medium and stabilised by suitable material. Normally cationic type emulsions are used in India. The bitumen content in the emulsion is around 60% and the remaining is water. When the emulsion is applied on the road it breaks down resulting in release of water and the mix starts to set. The time of setting depends upon the grade of bitumen.
Three types of bituminous emulsions are available, which are Rapid setting (RS), Medium setting (MS), and Slow setting (SC). Bitumen emulsions are ideal binders for hill road construction. Where heating of bitumen or aggregates are difficult. Rapid setting emulsions are used for surface dressing work. Medium setting emulsions are preferred for premix jobs and patch repairs work. Slow setting emulsions are preferred in rainy season.
Bitumen is used as a binder in road construction and in protective coatings and adhesives used in the construction industry. In the most common processes the bitumen is heated to 100–200° C until fluid enough to mix with aggregate.
Advantages and Uses of Bitumen Emulsions are:
•Bitumen emulsion are used extensively in bituminous road construction. Other than this they are used for maintenance and repair work.
•Emulsions can be used in wet weather even if it is raining.
•Bitumen emulation is also used in soil stabilization in desert areas.
•It doesn’t need extra heat while placing.
•There is no wastage in placing and laying of bitumen.
•They possess anti-stripping properties.
•Rapid setting type of emulsion are used in surface of roads.
•Medium setting type of emulsion are used in premixing of bitumen emulsion and coarse aggregate.
•Slow setting type of emulsion are used with fine aggregates as the surface area is large and requires time for uniform mixing.
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