What? Why? How?
When mixing asphalt, bitumen needs to be in a liquid state. This means that bitumen will be hot during handling. It is important, therefore, that everyone involved in handling bitumen and bituminous materials follows the relevant best practice guidelines and takes appropriate precautions.
Risks
Personal protection equipment
Approach
Mixing bitumen can be divided into three different purposes. This means three different approaches are needed.
Small scale mixing
For every purpose where less than 2 liters of bitumen needs to be mixed, hand mixing is sufficient*. Gently mix the bitumen with a spatula. A heating element can be used, but it's not necessary. Small scale mixing can be done by everyone.
Medium scale mixing
For bitumen mixing between 2 liters and 5 liters, the automatic mixer can be used. Gently put the automatic mixer in the hot bitumen (about half way in). When the mixer is stable, slowly turn it on. If you see that everything is going smoothly, the speed can be raised. Depending on the bitumen type, hand mixing is also an option. For more information, contact the lab manager. Medium scale mixing can be done by everyone who have gotten the specific instructions from the lab manager and/or lab assistant.
Large scale mixing
For every purpose where more than 5 liters of bitumen needs to be mixed, the automatic mixer is used. This kind of bitumen mixing can only be done by (or under supervision of) the lab manager and/or lab assistant.
*Polymer modified bitumen is preferably always mixed with the automatic mixer. Please contact the lab manager/-assistant for advice.