Emulsion Bitumen Applications 

Emulsion bitumen applications compared to normal bitumen (solid and semi-solid) or liquid bitumen (cut back) It is possible to avoid the need for a heating process at the time of use, the lack of the need for interdistillation solvents for the preparation of liquid bitumen, the non-ignition of fire during storage, transportation and use, as well as the non-contamination of the oil Biomass due to solvent evaporation (problem that In the case of liquid bitumen, it is possible to use it in construction, even with wet materials.

Emulsion Bitumen applications in cases such as the preparation of cold asphalt, surface asphalt, slurry seal, tack coat, etc., and in addition to that, they are used as mulch in the stabilization of liquid sand, protective coatings for tanks, etc They have a roof. Emulsion It is a two-phase mixture of two immiscible liquids in which the inner phase is dispersed in the form of fine particles inside the outer phase. The diameter of the particles in the emulsion is between 0.1-5 microns.

Therefore, the diameter of the particles is larger than that of true and colloidal solutions. Without the use of materials called emulsifiers, this suspension is not stable and two immiscible liquids (for example: water and oil) will quickly separate from each other and form two distinct phases. The reason for this problem is that due to the increase in the contact level between the two phases and as a result of the increase in the interfacial energy, the system has an unstable state or the separation of the two phases of the system reaches a stable state.

Emulsion bitumen applications difficulties

1- Improper ratio of oil and water phases

2- Improper choice or amount of emulsifier

3- Impurity in water, oil, or emulsifier

4- The reaction between the constituents together or with the container

5- Increase in temperature

6- Excessive evaporation

7- Freezing

8- Mechanical shock

9- Incorrect mixing time or speed

10- Absorption of gas or foreign substances

11- Presence of large particles in the dispersed phase Factors affecting the setting of emulsions bitumen applications In general, the factors affecting the setting of bitumen emulsions, which should be taken into account in determining the approximate setting time, after spreading the emulsion or mixing it with stone materials during the implementation of asphalt work and operations, are:

• Speed ​​of water absorption by aggregates: usually, stone materials with fine and porous texture accelerate the setting time of the emulsion (by absorbing the water in the system).

• Moisture and water percentage of stone materials before mixing with bitumen • Atmospheric conditions, including ambient temperature, relative humidity and wind speed, which have a decisive effect on the phenomenon of trapping.

• The load applied by the roller (during compaction operations) and road traffic: the pressure of the roller accelerates the outflow and removal of water to a limited amount.

• Structure and specific surface of stone materials: due to the specific surface, small structures accelerate the inclusion and breaking.

• Mineralogical composition of stone materials: Some types of stone materials enter into a chemical reaction with emulsion and accelerate the setting.

• Stone materials with soil or fines more than the specifications: these materials accelerate the breaking but delay the action.

• Amount and type of emulsifier used in the emulsion system

• Chemical coagulation caused by the instability of the emulsion: a condition where the emulsion becomes unstable due to the loss of water and precipitates.

Storage, maintenance of emulsion bitumen applications

The storage, transportation and transfer of emulsion bitumen applications requires following the instructions and important points beyond what are common for other types of consumer bitumen. Any tolerance and disregard for this stage of executive operations will cause premature and premature breaking of the emulsion, which ultimately makes the bitumen unusable and imposes a high cost on the project.

To heat bitumen, you can use hot water pipes or low pressure water steam installed inside the tank. The temperature on the surface of hot water pipes should never exceed 85 degrees Celsius. The temperature of bitumen in the storage tank should be selected according to the type of bitumen emulsion applications. The increase in bitumen water evaporates the water in the emulsion. As a result, the emulsion thickens and a layer of pure bitumen appears inside the tank. In such conditions, all bituminous materials inside the tank are unusable.

Compressed air should not be used to mix bitumen emulsion because it will cause the emulsion to break. Moving bitumen emulsion In moving, transporting and transferring bitumen from one tank to another tank, the following conditions and points should be observed: When we heat the bitumen emulsion to transfer it from one tank to another tank, it should be stirred to prevent it from sticking or reducing the thickness of the bitumen skin.

All pumps, faucets, communication pipes of storage tanks should be protected from freezing. Pumps should be emptied and cleaned in all conditions and washed, or use the anti-freeze recommended by the bitumen emulsion manufacturer. It is necessary to use pumps that the distance of the inner wall of the pump is suitable for bitumen transfer. Otherwise, the pump will stick and will not work. You should always use suitable pumps. Pumps should not be heated above 65 degrees centigrade to start working.

When the pump is used even for a short period of time, it should be filled with a petroleum solvent so that the pump can be turned on easily and freely. bitumen selection Anionic and cationic emulsion bitumens are divided into three main groups: quick-breaking, slow-breaking, and slow-breaking, and each has at least two sub-groups, which make a total of 17 different types of emulsion bitumen Rasand, that in choosing a specific and appropriate bitumen The conditions under consideration are special considerations