An emulsion is a bituminous binder which is in a fluid form at atmospheric temperatures above OoC and requires no heating at all. Bitumen cab be converted to an emulsion by using an emulsifying agent in the presence of water. The water content is nearly 40 per cent, and only the balance 60 per cent is bitumen. The advantages of an emulsion are:
(a) They can be used when the aggregates are wet.
(b) They need not be heated at site, and thus environmental pollution is minimised.
(c) They can be used in wet and cold weather.
(d) They are ideal for repair works.
(e) They can be used for sealing fine cracks since they can penetrate such cracks and seal them.
Where emulsion is applied on the road it breaks and the water evaporates, leaving behind only bitumen.