Bitumen Emulsions. During road and civil construction and repairs, bitumen emulsion are used in the same manner as non-emulsified binders, such as bitumen.
When mixing mineral materials with emulsions, the latter separate and the surface of the rock is covered with a thin layer of the binding materials. The strength of adhesion of this film depends on the properties of both the emulsion and the mineral. Adhesion is best when treating basic mineral surfaces.
The rate of emulsion breaking on contact with the mineral is important. All jobs have a certain tempo, and the longer the job, the more stable the emulsion should be.
The emulsion used currently can be quick, medium or slow setting.
A quick breaking emulsion separates soon after application to the mineral. Average time of breaking is 10 to 30 minutes. Medium breaking emulsion separate in a moderate amount of time, such as 30 to 60 minutes, while slow breaking emulsions separate in hours or days. Separation of quick and medium breaking emulsions occurs due to the presence of water and the influence of the mineral material, while slow breaking emulsions separate primarily due to water evaporation. Water-in-oil emulsions are medium breaking.
The rate of separation depends on the quantity and properties of the emulsifier in the emulsions. Increasing the amount of emulsifier slows the separation.
Apart from the required breaking rate, bitumen emulsions for road construction must meet the following criteria:
- The content of bitumen in the emulsion must be 50-60% by weight.
- Emulsion must be uniform. This is tested by filtering the emulsion theough a 0.15 mm sieve. The remaining material must not exceed 0.5% of the emulsion weight.
- Viscosity of the emulsion must be sufficient for distribution by available machines and to form a thick enough film on the mineral material after application. Viscosity measured by a standard viscometer with 3mm orifice at 20ºС must be 10-30 s.
- The emulsion must be stable in storage of 1-2 months, including mechanical shocks which occur during transportation and handling.
Using emulsions for road construction has several advantages over straight bitumen:
- emulsion can be applied cold, eliminating the need for special heating equipment;
- emulsions can be applied to moist mineral material, and work can continue in damp and cold weather with ambient temperature as low as +10ºС, if water-in-oil emulsions are used with oil-in-water emulsions. This factor extends the construction season and improves the annual efficiency of construction machinery;
- formation of a thin binder film on the mineral surface, saving up to 25-30% of the binder without degrading material strength.
GlobeCore manufactures equipment for bitumen emulsions of any type. For independence from the construction material market, a UVB-1 machine is sufficient to make enough emulsions for current construction projects. GlobeCore equipment are compact, equipped with a protective measures and makes emulsion which meets all the leading world standards.