Bitumen Emulsions are classified in British Standard (also Kenya Standard & Australia standard) which being defined by a three-parts.

1. The first part, either A or K, indicates anionic or cationic emulsion.

2. The second, 1 to 4, indicates the breaking rate or stability (the higher the number, the greater the stability or the slower the break).

3. The third part of the code indicates the bitumen content of the emulsion as a percentage of the total.

for example ;
K1-70: a cationic emulsion, rapid breaking with a bitumen content of 70%
A2-50: an anionic emulsion, semi-stable with a bitumen content of 50%.

The Standard specifies bitumen emulsions in terms of:

• Particle charge;
• Sieve residue 1 (coarse sieve, 710mm);
• Sieve residue 2 (fine sieve, 150mm);
• Viscosity is an efflux time from a flow cup (degrees Engler or Redwood II seconds);
• Coagulation at low temperature;
• Storage stability (short period test);
• Storage stability (long period test);
• Stability of mixing with coarse aggregate;
• Stability of mixing with cement;
• Bitumen content*.

* The test method specified in fact measures water content with ‘bitumen content’ defined as the difference between water content and 100%, thus ‘bitumen content’ includes emulsifier and solvent.