Emulsion Sieve Prevention

The formation of a sieve or coarsening in an asphalt emulsion is a common issue that can affect the stability and performance of the emulsion. Several factors can contribute to the formation of a sieve:

• Emulsion Composition: The proportions and type of raw materials used to produce the emulsion can influence sieve formation. The ratio of asphalt to water to emulsifying agent and the quantity of emulsifying, co-emulsifying & stabilizing agents can impact the stability of the emulsion.
• Emulsifying Agent: The choice of emulsifying agent is crucial for creating a stable asphalt emulsion. Different emulsifying agents have varying effects on the emulsion's properties & stability and using the wrong emulsifier for certain binders or an inadequate amount of emulsifier can lead to sieve formation.
• Temperature: Emulsification is temperature sensitive. Inadequate temperature control results in a higher or lower temperature than required during the production process. This can negatively affect emulsion stability, leading to sieve formation over time.
• Particle Size Distribution: The particle size distribution of the dispersed asphalt droplets in the emulsion plays a vital role in preventing the formation of sieve. Larger droplets may aggregate and separate from the emulsion, leading to sieve formation. See the previous Emulsion Notes on Particle Size for more information.
• Storage and Handling: Improper storage and handling of the emulsion after production can also contribute to sieve formation. Exposure to extreme temperatures, excessive pumping or mixing or long-term storage without proper agitation can lead to sieve in the emulsion.
• Water Quality: The quality of water used in the emulsification process can impact the stability of the emulsion. Hard water for anionic emulsions or water containing organic impurities for any emulsion may affect the emulsion's performance and lead to sieve formation.