Workability agents

Workability is one of the most important characteristics of concrete especially under the following circumstances:

1. If the concrete is to be placed around closely placed reinforcement or in difficulty accessible sections.
2. Where special means of placement are required such as tremie, chute or pumping methods.
3. If the concrete is harsh because of aggregate characteristics or grading

The materials used as workability agents are:

1. Finely divided material
2. Water reducing agents 
3. Air entraining agents

• Common materials added as workability agents are bentonite clay, diatomaceous earth, fly ash, finely divided silica, hydrated lime and talc
• When they are added and if the quantity of water is not reduced they greatly increase the workability.