Factor affecting "workability"of concrete

i)Water content - More water than specified increase the fluidity but less the strength. Proportioned amount of cement may be used to keep the W/C ratio as specified which does not affect workability.

ii)Mix proportion -If the aggregate /cement ratio is high the concrete is lean and less quantity of paste is available for lubricating decreasing workability.

iii)Size of aggregate - For a given quantity of water and paste a bigger size of aggregates gets after less surface area given higher workability.

iv)Shape -Surface texture aggregates: For a given volume rounded aggregate provide less surface area and less void then angular or flaky shapes, the frictional is greatly reduce and thus they provide greater workability.

v)Grading of aggregates -Well-graded aggregates has the least voids thus increase workability.

vi)Using of admixtures -Use of plasticizer and super-plasticizer improve the workability to lowering the water-cement ratio.