Tag Archives: quality tests on concrete

Vee Bee Consistometer test – Workability of concrete

Vee Bee Consistometer Test is a reliable laboratory method used to evaluate the workability of concrete, especially for stiff and low-workability mixes where slump test results are not accurate. The Vee Bee Consistometer test for workability of concrete measures the time required for concrete to remould under vibration, providing a clear indication of consistency. In the workability of concrete Vee Bee test, vibration energy replaces gravity-based flow, making it suitable for dry mixes. Understanding the Vee Bee test procedure helps engineers achieve consistent and repeatable results. The Vee Bee Consistency test of concrete is widely used in laboratories and quality control setups and is considered one of the most dependable tests for workability of concrete for controlled assessment of stiff concrete mixes.

This article explains the Vee Bee Consistometer test, its principle, procedure, applications, and importance in accurately assessing the workability of stiff concrete mixes.

Significance of Quality tests on concrete

Quality tests on concrete are essential for ensuring strength, durability, and performance in construction. These tests help engineers assess the workability of fresh concrete and the quality of hardened concrete. Common quality tests on concrete include checks during the production stage (on fresh concrete before placing), tests on hardened concrete specimens, and evaluations performed directly on finished structures. Including tests like the flow table test for concrete ensures reliable results and consistent quality throughout a project.

A construction worker in a safety vest and hard hat examines concrete samples next to a compression testing machine in a lab setting.
A civil engineer in a safety helmet and reflective vest analyzing concrete test specimens in a lab, showcasing the importance of quality control in concrete workability tests.

Quality tests performed on concrete are classified into

  • Production stage quality tests ( On fresh concrete before placing)
  • Hardened stage quality tests ( hardened concrete specimens)
  • Non Destructive tests On structures ( tests done on the structures )

Also read : Aggregate Crushing test – Strength of aggregate

Also read : 9 lab tests of Bitumen for flexible pavements

Production stage quality tests on fresh concrete

Production stage quality tests on fresh concrete are crucial for ensuring the right workability and consistency before placement. These tests help engineers select the best mix for construction and maintain quality control. Key tests include the slump test, compaction factor test, Vee-Bee test, Kelly ball test, and the flow table test for concrete.

This article focuses on the Vee Bee Consistometer test, explaining its procedure, importance, and how it compares with other workability tests like the slump test and compaction factor test.

Vee Bee Consistometer test for workability of concrete

The Vee Bee Consistometer Test is a laboratory test used to determine the workability of concrete, particularly stiff and low-workability mixes. It measures the time required for fresh concrete to remould from a conical shape into a cylindrical shape under controlled vibration. This time, known as the Vee Bee time, indicates concrete consistency. Unlike the slump test, the Vee Bee Consistometer test for workability of concrete is suitable for dry mixes that do not flow easily. Commonly used in quality control, this test helps engineers compare mix designs and ensure uniform concrete performance.

A steel laboratory apparatus used for material testing, featuring a cone-shaped container and a mechanical device for precise measurements.
Vee Bee Consistometer apparatus used for evaluating the workability of concrete in laboratory settings.

Relevant Codes and Standards for Vee Bee Consistometer Test

  • IS 1199 (Part 2): 2018Methods of Sampling and Analysis of Concrete – Workability
    Issued by Bureau of Indian Standards.
    This standard covers the Vee Bee Consistometer test, along with slump and compaction factor tests.
  • BS EN 12350-3Testing Fresh Concrete – Vebe Test
    Issued by British Standards Institution.
    Widely used in the UK and Europe for stiff concrete workability assessment.
  • DIN 1048 (Part 1)Testing Concrete – Fresh Concrete Tests
    Issued by DIN.
    Includes the Vebe test for consistency measurement.

Note: These standards ensure uniform testing procedures, repeatable results, and reliable evaluation of low-workability concrete mixes.Relevant IS code

Apparatus used for Vee Bee Consistometer

A blue industrial machine with a funnel and a black container at the center, designed for processing materials.
Vee Bee Consistometer apparatus used to assess the workability of concrete.

The Vee – Bee Consistometer includes of 

  • A vibrator table resting upon elastic supports
  • A metal pot
  • A sheet metal cone, open at both ends
  • A standard iron rod

The dimension of the vibrating table is 380 mm in length, 260 mm in width and height of 305 mm. Also, supporting the table there is a rubber shock absorber. Under the table, there is a vibrator that vibrates electrically.  The dimension of the metal slump cone is 300mm height, 200 mm top diameter and 100 mm bottom diameter. 

A person pouring a scoop of material into a metallic measuring cone on a balance scale, with a blue background.
The Vee Bee Consistometer, essential for evaluating the workability of concrete, particularly in stiff and low-workability mixes.

Test procedure

  • Initially fill the slump cone with four layers of concrete. Each layer should have a height of one – fourth of the cone. 
  • After that tamp each layer 25 times using a standard tamping rod and strike uniformly.
  • Then after placing the final layer, remove the excess concrete on the top of the concrete.
  • Move and place the swivel arm attached to the glass disc on the top of the cone.
  • Now remove the cylindrical cone gradually in the vertical direction and note down the slump.
  • Then switch on the electrical vibrator and allow the concrete to spread. 
  • The time taken by the concrete to spread uniformly is noted using the stop clock.
  • This time is expressed in vee bee seconds.

The time for the concrete to remould is the Vee-Bee seconds. The Vee Bee consistometer is an indirect measure of concrete workability. This method is suitable for concrete whose slump value cannot be determined. ie, for dry mixes. We can get direct result through this method.

Also Read : Soundness test on aggregate

Key Takeaways

  1. The Vee Bee Consistometer Test is designed to assess the workability of stiff concrete mixes.
  2. It measures the time required for concrete to remould under vibration.
  3. Longer Vee Bee time indicates lower workability of concrete.
  4. The test provides more reliable results than slump test for dry mixes.
  5. It is commonly used in laboratory-controlled environments.
  6. The method helps compare different concrete mix designs.
  7. Proper vibration is essential for accurate results.
  8. The test minimizes subjective judgment during workability assessment.
  9. It is standardized under Indian and international codes.
  10. The test is an important part of quality control procedures.
  11. It complements other tests for workability of concrete.
  12. It ensures consistency during concrete production.

Conclusion

The Vee Bee Consistometer Test plays a crucial role in evaluating the workability of concrete, especially for mixes with low water content. By measuring the remoulding time under vibration, the test provides a clear and quantitative indication of concrete consistency. Unlike the slump test, it performs well for stiff mixes where flow is minimal. When conducted according to standard procedures, the test helps engineers maintain uniformity in concrete production and placement. It also supports effective quality control by enabling comparison of different mix proportions. As one of the reliable laboratory-based tests for workability of concrete, the Vee Bee Consistometer Test remains essential for achieving durable and well-performing concrete structures.

Compaction factor test – Workability of concrete-Test procedure

Compaction factor test is conducted to determine the workability of the concrete. Compaction factor test is a lab test and is generally conducted on concrete samples having very low workability.

Concrete is designed for a particular strength. The total structural stability is dependent on a good quality concrete. That is why quality control is one of the most important aspects taken into account during the production of concrete . A little variation in water to cement ratio, ingredient proportioning, increase in slump etc will have a major impact on the desired strength of the structure which in turn affects the structural stability.

Quality tests on concrete

Following are the stages of quality tests

  • Production stage quality tests ( On fresh concrete before placing)
  • Hardened stage quality tests ( hardened concrete specimens)
  • On structures ( tests done on the structures )

Production stage quality tests to determine workability of fresh concrete

This article is about Compaction factor test.

Significance of compaction factor test

Concrete is designed for a strength. The total structural stability is dependent on the concrete quality and strength. Because of that, the concrete quality has to be controlled and ensured in the production stage. Even marginal variations in water to cement ratio, ingredient proportioning, increase in a slump, etc. tend to impact the desired concrete strengths.

Compaction factor test.

Compaction test is for determining the workability of concrete. Workability of concrete is defined as the ease and homogeneity with which a freshly mixed concrete or mortar can be mixed, placed, compacted and finished. Strictly, it is the amount of useful internal work necessary to produce 100% compaction.

Compaction factor test is developed by road research laboratory UK and is precise and accurate than slump test. The test is done when the concrete is to be compacted by vibration and continually fail to slump.

Also read : Bitumen – 9 lab tests on bitumen for flexible pavements.

Also read : Timber – Five important quality tests

Compaction Factor Test – Relevant IS code 

IS: 1199- 1959

Apparatus used

Compaction test apparatus
Compaction test apparatus
Dimensions of compacting factor apparatus
Dimensions of compacting factor apparatus
  • Compacting factor apparatus
  • Cylindrical mould 
  • Hand scoop 
  • Trowel
  • Weighing machine

The figure shows the dimension of the hopper and the mould. The inside area of the hopper should be smooth. The apparatus is made of bronze or cast brass. At the lower ends of the hopper, there is a trap door with a 3mm thickness. A rigid frame attaches the hoppers and cylinder. After the completion of mixing, the test is conducted at a constant time interval. 

Test procedure

  • Place the sample in the upper hopper of the apparatus using a hand scoop.
  • Fill the hopper with its brim level and open the trap door.
  • Then allow the concrete to fall into the lower hopper.
  • Immediately after the concrete rests, uncover the cylinder and open the lower trap door.
  • Cut off the excess amount of concrete above the cylinder using the trowel.
  • Then weigh the concrete in the cylinder nearest to 10g. This is the weight of partially compacted concrete.
  • Refill the cylinder with the same sample in the layers and the layer is heavily rammed or vibrated for full compaction.
  • Then weigh the fully compacted concrete and the weight of the empty cylinder.
  • Finally, Compute the compaction factor using the formula.

The compaction factor is the ratio of partially compacted concrete to fully compacted concrete.

Compaction factor = (W1 – W) / (W2 – W)

The compaction factor value varies from 0.7 to 0.95.