Which of the following statement(s) is/are true regarding Vee-Bee consistometer test? (i) It is suitable for very dry concrete mixes. (ii) It measures time required for concrete to change shape under vibration.
- AOnly (i)
- BOnly (ii)
- CBoth (i) and (ii)Correct
- DNeither (i) nor (ii)
Solution
Concept
Vee-Bee consistometer workability evaluation
Formula
NONE
Step-by-step solution
1. The Vee-Bee consistometer measures the remolding effort needed to transform fresh concrete from a conical to a cylindrical shape under standard vibration. 2. It is especially suited for very stiff, dry mixes with zero or very low slump (slump < 25 mm); statement (i) is true. 3. The recorded metric (Vee-Bee degrees) is the time in seconds taken for the transparent plastic disc to become completely coated with cement grout; statement (ii) is true. 4. Hence, both statements (i) and (ii) are true. Answer: C
Explanation
The Vee-Bee consistometer test is specifically intended for measuring the workability of very dry, stiff concrete mixes with low slump that cannot be reliably assessed by standard slump cones. It subjects a remolded slump cone of concrete inside a cylindrical container to mechanical vibration, measuring the elapsed time in seconds for the surface to become completely horizontal.
Why the other options are wrong
A) Statement (ii) is also true, as the test directly measures remolding time in seconds under vibration. B) Statement (i) is also true, as Vee-Bee is specifically designed for very low workability mixes. D) Both statements accurately reflect the standardized test procedure in IS 1199.
Shortcut
Vee-Bee test = Stiff/dry mixes + Time (seconds) under vibration for shape transformation.
Common mistake
Believing Vee-Bee test is for high-workability or self-compacting mixes.
Correct answer: C) Both (i) and (ii)