Bitumen emulsion is a key component in modern road construction and maintenance, playing a vital role in enhancing the durability and performance of road surfaces, as well as helping to meet industry sustainability targets by lowering emissions associated with road construction. Throughout this blog, we’ll provide information on what bitumen emulsion is, the production process, the various types and their applications.
What are bitumen emulsions?
Bitumen emulsion is a specialised mixture composed of bitumen, water, and emulsifying agent. This formulation is designed to lower the viscosity of bitumen, making it easier to work with during the road construction process at lower temperatures. The primary purpose of bitumen emulsion is to create a protective layer that seals roads, shielding them from the harsh effects of weather, traffic and other environmental factors.
How is bitumen emulsion created?
The production of bitumen emulsion involves a strict process that blends water, an emulsifying agent, and other chemical additives with bitumen. Here’s a breakdown of the process:
1. Water and Emulsifier Mixture:
Water is combined with an emulsifying agent and other chemical agents to create a stable base for the emulsion.
2. Colloidal Mill Addition:
The water-emulsifier mixture is introduced into a colloidal mill, where it is mixed with bitumen. The amount of bitumen added depends on the intended application of the final product.
3. Creating Surface Charge:
The emulsifying agent envelops each bitumen droplet with a coating surface charge. This unique feature ensures that the bitumen droplets remain dispersed and suspended, facilitating their effective mixing with water.
Types of bitumen emulsions
Bitumen emulsions are classified into two main types, based on setting time and surface charge, these include:
Based on setting time
Slow Setting Emulsion
This type of emulsion is designed for applications that require a gradual process of water evaporation. It features a relatively stable emulsifying agent.
Medium Setting Emulsion
These emulsions are specifically formulated to prevent breaking when applied to aggregates. The process of evaporation starts when fine mineral dust mixes with the aggregate-emulsion mixture.
Based on Surface Charge
Anionic Bitumen Emulsion
In this type, tiny droplets of bitumen carry a negative charge. This facilitates better interaction with aggregates in certain mineral compositions.
Cationic Bitumen Emulsion
Tiny droplets of bitumen in cationic emulsions are electro-positively charged. Their usage depends on the mineral composition of the aggregates.
Bitumen
emulsions are suitable for a range of applications in road construction due to
their versatility and performance-enhancing properties. From creating durable
road surfaces to protecting roads from the elements, bitumen emulsions play a
crucial role in modern infrastructure development.
The global move away from environmentally harmful cutback bitumens to bitumen emulsions is causing a large increase in the use of emulsions, representing the industries shift towards a more sustainable path.
As road technology continues to evolve, bitumen emulsions remain a key player in ensuring safe and resilient road networks for communities around the world, whilst also ensuring the road construction sectors do their part in the push for a more environmentally conscious industry.
