Bitumen emulsions are a versatile and environmentally superior method of binding aggregates. Bitumen must be made mobile to wet out and adhere to an aggregate. This process may be carried out by heating, cutting with solvents, or emulsification. When the wetting has occurred, the bitumen must revert to its semi-solid state. Retained solvents can create long-term softness, and if the bitumen cools too quickly, it may not allow processes like compaction. In emulsions, we have a chemical system that may be manipulated for the properties required. With bitumen, we make oil in water type emulsion.  That is, water is a crucial component to ensure that evaporation is not the controlling mechanism of becoming solid chemistry is used.

Description:

 

1. Bitumen emulsion are water in oil dispersions; they are non-toxic in agriculture and aquaculture

2. The material is stabilized by a surfactant system- a bit like shampoo.

3. Bitumen is heated and blended with a surfactant solution and any desired additives, like rejuvenator, break controller, stability controller, or polymer.

4. The resulting emulsion application is determined by chemistry, binder content, binder type, and additives.

5. Emulsions may be used for any road application. They include priming, tack coat, waterproofing, membranes, chip sealing, rejuvenation seals, micro-surfacing, stabilization, CIPR, cold-mix. It can even be formulated to promote germination in agriculture.

6. Emulsions are designed for the application, the break rate, the cure rate, and the ability to form cohesive adhesive films on aggregate.

7. Emulsions are made by high shear mixing of bitumen into microscopic round droplets 1-10microns in diameter. The chemical system forms an equilibrium between the water and the bitumen phase. This is called the double layer. The double-layer can be manipulated by chemistry in thickness and stability. This is the so-called zeta potential and can control both break and cure

8. ART and their advisors have half a century of expertise in emulsions. They produce a range of emulsions from specification compliant to advanced technology materials.

 

Essential aspects:

 

1. The elements are thus :

    a. Colloid mill

    b. Bitumen type and chemistry

    c. Performance requirements in application and service

    d. Design for climatic conditions, especially to adjust cure time

    e. Shear resistance for pumping

 

2. The application is first determined:

    a. Required break rate – rapid, medium, or slow. This will determine things such as mixing time and reaction with different aggregate types

    b. Required cure time under application conditions

    c. Storage time for cold mix

    d. Binder chose for performance

 

3. Traffic and constructability

 

4. Manufacture

    a. Colloid mill

    b. Tight temperature and shear control to control the particle size distribution

    c. Precise metering so in the colloid mill there is always the correct proportions.