Degree of workability

Slump (mm)

Compacting factor

Use for which concrete is suitable

Small apparatus

Large apparatus

Very low

–

0.78

0.80

Roads vibrated by power-operated machines. At the more workable end of this group, concrete may be compacted in certain cases with hand-operated machines.

Low

25 – 75

0.85

0.87

Roads vibrated by hand-operated machines. At the more workable end of this group, concrete may be manually compacted in roads using aggregate of rounded or irregular shape. Mass concrete foundations without vibration or lightly reinforced sections with vibration.

Medium

50-100

0.92

0.935

At the less workable end of this group, manually compacted flat slabs using crushed aggregates. Normal reinforced concrete manually compacted and heavily reinforced sections with vibration.

High

100-150

0.95

0.96

For sections with congested reinforcement. Not normally suitable for vibration, for pumping and tremle placing.

Very high

–

–

–

Flow table test is more suitable.