Question

Workability of concrete can be measured using slump, compaction factor and Vee bee time. Consider the following statements for workability of concrete.
(i) As the slump increases, the Vee bee time increases
(ii) As the slump increases, the compaction factor increases

Which of the following if TRUE?

• A. Both (i) and (ii) are True
• B. Both (i) and (ii) are False
• C. (i) if True and (ii) is False
• D. (i) is False and (ii) is True

Answer 1

The correct option is D (i) is False and (ii) is True

Slump is the subsidence of the specimen recorded in mm. As slump increases, water content increases

$\Rightarrow$ Workability increases
$\therefore$ Compaction factor = Mass of partially compacted concrete/ Mass of fully compacted concrete

$\Rightarrow$CF wil also increase
Vee bee time is the time required for transforming by vibration, a concrete specimen in the shape of a conical frustum into a cylinder. Hence, as workability increases, Vee bee time decreases.