The Constructor

Tests for Workability of Concrete at Construction Site and Recommended Values

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Various tests for workability of concrete at construction sites i.e slump test, Vee-bee test, Compaction factor test and its recommended values are given below. What is workability of concrete and What are tests is generally performed at site for its determination? And what are its recommended values for different purposes? Workability of concrete describes the ease or difficulty with which the concrete is handled, transported and placed between the forms with minimum loss of homogeneity. Workability is important because, if i. the concrete mixture is too wet, coarse aggregates settle at the bottom of concrete mass and as a result concrete becomes non-uniform composition, ii. the concrete mixture is too dry, it will be difficult to handle and place it in position

Tests for Workability of Concrete

Workability of a concrete mixture is measured by: a) Vee-bee consistometer test b) Compaction factor test c) Slump test The first two tests are laboratory tests while the third test is the field test.

Concrete Slump Test

This test is carried out with a mould called slump cone whose top diameter is 10cm, bottom diameter is 20 cm and height is 30 cm. the test may be performed in the following steps: 1. Place the slump mould on a smooth flat and non-absorbent surface. 2. Mix the dry ingredients of the concrete thoroughly till a uniform colour is obtained and then add the required quantity of water. 3. Place the mixed concrete in the mould to about one-fourth of its height. 4. Compact the concrete 25 times with the help of a tamping rod uniformly all over the area. 5. Place the concrete in the mould about half of its height and compact it again. 6. Place the concrete up to its three fourth height and then up to its top. Compact each layer 25 times with the help of tamping rod uniformly. For the second subsequent layers, the tamping rod should penetrate into underlying layers. 7. Strike off the top surface of mould with a trowel or tamping rod so that the mould is filled to its top. 8. Remove the mould immediately, ensuring its movement in vertical direction. 9. When the settlement of concrete stops, measure the subsidence of the concrete in millimeters which is the required slump of the concrete.

Figure: Measurement of slump

Suitability of Slump Test:

The slump test is suitable only for the concrete of high or medium workability.

Recommended Values of Concrete Slump Tests for Various Purposes:



Types of concrete






Concrete for road construction


20 to 40 mm




Concrete for tops of curbs, parapets, piers, slabs and wall


40 to 50 mm




Concrete for canal lining


70 to 80 mm




Normal RCC work


80 to 150 mm




Mass concrete


20 to 50 mm




Concrete to be vibrated


10 to 25 mm

Read More: What Is Workability of Concrete? Workability vs. Strength of Concrete Concrete Slump Test – Procedure and Results Factors Affecting Workability of Concrete Concrete Workability – Slump & Compacting Factor Values and Uses Vee-Bee Test to Determine Concrete Workability using Consistometer
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