Workability Of Concrete
Workability Of Concrete:
Workability can be defined as the property of fresh concrete which describes the ease and homogeneity of the concrete to be mixed, fully compacted and finished. A workable concrete should possess following two requirements:
1. The concrete should be compacted with minimum efforts.
2. The concrete should not form bleeding and segregation.
Workability of concrete mainly depends on the mix proportion and the properties of concreting materials (water, cement, aggregates). The shape, size, and grades of aggregates also play a great role in the variation of workability. For better workability fine and coarse aggregates should be well graded. It has been found that concrete made of round grain sand is more workable than the concrete of crushed sand. If air entraining admixture is used in the mix, it will also increase the workability and decrease segregation and bleeding.
Factors Affecting Workability Of Concrete:
The factors affecting workability are as following:
1. Amount Of Water In The Mix:
2. Proportion Of Coarse And Fine Aggregates: Workability can be increased by decreasing the amount of coarse aggregates in the mix. Fine aggregates produce more wore workable concrete.
3. Shape Of aggregates: Round shaped aggregates give better workability than angular shaped aggregates.
4. By expanding the cement content in the mix.
5. By including admixtures in the mix.
Apparently, the necessity of workability differs as per the nature of the job and blockage in the full stream of concrete due to the spacing and nature of the reinforcement. The workability of concrete is generally measured by one of the following three tests.
1. Slump Test.
3. Vee-Bee Test.