The word “Vee Bee ” was first derived from Sweden. V. Bahrner is the inventor of this Vee Bee Consistometer test. It’s a pure library test that measures workability of fresh concrete. Under Vee Bee Consistometer test, the workability is measured on the basis of movement and compactibilty. This Vee Bee test is appropriate for only dry concrete whose slump is greater than 50 mm in size.
For a construction industry, this activity or test takes a long time to happen. Vee Bee test changes the mass of concrete from a certain shape to another one using vibration process i.e., from the conical shape to cylindrical shape. The Vee Bee test is used to fix the uniformity of fresh concrete. It exposes the concrete samples to vibrations after eliminating the slump cone.
Concrete workability test
Concrete workability test means the ease and consistency of working with fresh mixed concrete. The aim of this work or test is to produce 100% compaction. A high consistency concrete needs no workability tests. To check or test the workability of concrete, one must go through the process of Concrete mixing, Concrete transportation, Concrete placing and the Concrete compacting. Some other facts also need to be considered like thickness of unit, mode of compaction, type of work and reinforcement. Under concrete workability tests, wet concrete is more workable than dry concrete.
To test the workability of concrete, it’s best to divide the concrete in three parts like low workability, medium workability and high workability. Many factors can affect Concrete workability like weather conditions and type of ingredients that are used for making the concrete. Several methods are used to test concrete workability like Vee Bee Slump test, Concrete consistency test, usage of slump instruments etc.
Vee Bee slump test
To measure the workability of freshly mixed concrete, we use the Vee Bee Slump test. The quality of concrete must be accurate. It should not be very dry or very wet. High workability concrete is only used for this Vee Bee Slump test. We will use a systematic tool called Slump cone for this Vee Bee test. Let’s perform this test in a science library as well as at site.
We will follow these steps for slump test: –
- Take a cone shape mold named slump of top diameter 100 mm, bottom 200 mm and height must be of 300 mm
- As per ISC (Indian standard specification) norms, size of concrete must be 38 mm
- Now mix all ingredients of concrete and wait for some time to settle down its final color
- Put the mixed and uniform colored concrete in mold in three layers
- With the help of tamping rod, we will divide concrete in three layers
- In first layer, we will fill the mixture of about one fourth of mold’s height
- We will fill the second layer with concrete mixture of about half of mold’s height
- Similarly, this time we will fill concrete mixture about three fourth of its height
- Each layer must be 25 times more with the help of standard tamping rod
- In end, when the concrete gets settle then measure the settling concrete in millimetres as if the concrete reduces equally to all round to 5mm, then it is a true slump
- The test must be repeated for the completion of process if one half of the cone is in inclined plane state.
Slump measurement instrument
This test involves low-cost tools. Slump tests can be easily and quickly done by Slump measurement instruments. The construction industries are majorly using these Slump instruments. These Slump measurement equipment or instruments are as follow: –
Tamping Rod: For filling the accurate amount of concrete mixture, we use it. Tamping rods are used for measuring the expanse slump.
CSC (Concrete Slump Chart): This chart tells us about the various range of slump values and their applications. It also gives us absolutely the data about the size of slumps and their workability as in very low, low, medium or high functioning.
Funnels: Funnels are vessels or containers made up of aluminum to use in filling. We use funnels with slump cones for assisting.
SSC (Standard Slump Cone): SSC are steel and plastic cone shaped molds. These slump cones resist rusts and can be clean with acid wash. For testing concrete thickness, we use these cones.
Trowels: It is a flat pointed blade which is made of aluminum. There is a wooden handle used for filling edges. Trowels are having edged and sharped boundaries. Its dimensions are 70×127 mm.
SBP (Slump Base Plate): Slump base plates are made of strong metal named as aluminium. We use SBP for holding all slump cone models. With the help of a Slump base plate, a person can easily perform his test. The movable handles of SBP are use for measuring slump.
Scoops: Scoops are used for collecting concrete. Its dimensions are mostly 210 mm length, 133mm width and 76mm depth.
Brushes: These are acid proof wooden handles with rough feathers. We use this equipment at the end of the experiment. We use brushes to clean the extra concrete off after completing the test.
Concrete consistency testing
Consistency is the constancy or relative movement of concrete mixture for completing its process. We will follow these steps to test the Consistency of concrete or cement: –
- Take nearly 400 grams of cement and mix it with calculated amount of water needed
- The mixing time should not exceed 5 minutes
- Now fill the mixture in the mould to the top and level it with gloves
- Let the mixture settling to surface of vessel
- Note down the reading on the metre scale
- The reading on the metre scale must be between 5 to 7 mm
- If the cement concrete size must not be of 5 to 7mm then repeat the above procedure until it leads to its correct reading
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