Workability of Concrete | Improving Workability | Factors Affecting Workability

Workability is one of the physical parameters of concrete which affects the strength and durability as well as the cost of labor and appearance of the finished product. Concrete is said to be workable when it is easily placed and compacted homogeneously i.e without bleeding or Segregation. Unworkable concrete needs more work or effort to be compacted in place, also honeycombs &/or pockets may also be visible in finished concrete.

Definition of Workability

The property of fresh concrete which is indicated by the amount of useful internal work required to fully compact the concrete without bleeding or segregation in the finished product.

Factors affecting workability:

1. Water content in the concrete mix
2. Amount of cement & its Properties
3. Aggregate Grading (Size Distribution)
4. Nature of Aggregate Particles (Shape, Surface Texture, Porosity etc.)
5. Temperature of the concrete mix
6. Humidity of the environment
7. Mode of compaction
8. Method of placement of concrete
9. Method of transmission of concrete

How To improve the workability of concrete

1. Increase water/cement ratio
2. Increase size of aggregate
3. Use well-rounded and smooth aggregate instead of irregular shape
4. Increase the mixing time
5. Increase the mixing temperature
6. Use non-porous and saturated aggregate
7. With addition of air-entraining mixtures

An on site simple test for determining workability is the SLUMP TEST.