ACI Certification Practice Exam

When lifting the slump cone, it is crucial that it remains upright without rotation. This is important to ensure that the sample's integrity is maintained and the measurement of the slump accurately reflects the material's consistency and workability. Lifting the cone straight upward preserves the shape and volume of the concrete being tested, allowing for a precise assessment of its slump value.

If the cone were to be twisted or dropped quickly, it could introduce inaccuracies in the slump measurement, as these actions might disturb the concrete sample and lead to unintended deformation or displacement. Similarly, angling the cone could yield unreliable results by disrupting the uniformity of the material within the cone, thus affecting the slump reading.