Slump and Compacting Factor Test Values and Uses in Concrete Workability

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Slump test and compacting factor tests are the most widely used workability tests for concrete. The degree of workability of concrete depends on the values of test results obtained from slump test and compacting factor tests.

There are many types of concrete construction, and each type has different workability requirements. Following tables shows the degree of concrete workability based on the results of slump tests and compacting factor tests. The range of results of each these tests indicates the suitable uses of concrete work. The slump and compacting factor test values shown below are of concretes with 20mm or 40mm maximum size of aggregates.  

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.

Read More: Various Tests for Workability of Concrete at Construction Site and Recommended Values What Is Workability of Concrete? Workability vs. Strength of Concrete Concrete Slump Test – Procedure and Results Factors Affecting Workability of Concrete Vee-Bee Test to Determine Concrete Workability using Consistometer