Bitumen emulsions are actively used in almost all developed countries for road construction. They are used both in construction of new and repair of existing roads.
For example, in France about 30% of produced bitumen is emulsified. It is no coincidence, since working with bitumen emulsion improves quality, reduces duration and costs of road construction works.
But as they say, there is always room for improvement. In many cases conventional bitumen emulsions lack adhesive properties, reducing the potential durability of the upper layer of the road surface. Modified bitumen emulsions have higher performance and improves the quality of adhesion between layers.
Now, the term “modified bitumen emulsion” means an emulsion obtained by emulsifying modified bitumen and emulsions based on unmodified bitumen, but with introduction of modifier to water phase or directly into the emulsion during its preparation.
Composition of modified bitumen emulsions
A modified bitumen emulsion has three main components: polymer, bitumen and water. Various polymers are used to improve the physical and mechanical properties:
- Elastomers (synthetic rubbers);
- Thermosetting polymers;
- Block copolymers of butadiene and styrene.
Bitumen-latex emulsion – is a mixture of bitumen emulsion and latex. Latex is a water based dispersion of thermoplastic polymers with nonlinear structures.
To produce this material latex is prepared, then added to water phase. Further process does not differ from standard production of bitumen emulsions.
Modifying bitumen emulsion with latex substantially reduces the time of layer setting as compared to unmodified emulsions. In terms of pavement layer, it is virtually identical.
Production of latex modified bitumen emulsion
For production of latex modified bitumen emulsion GlobeCore offers its UVB-1 unit with latex injection unit. The customer may purchase the equipment with latex unit already installed or as an additional assembly part.
Latex can be injected into water or bituminous phase and also into the ready emulsion. This versatility makes it very attractive to manufacturers.
However, in production of polymer modified bitumen emulsions it is necessary to consider compatibility of the chosen type of polymer and bitumen phase. Neglecting this factor may result in product that doesn’t have the desired properties.