ACI Certification Practice Exam

When raising the slump mold, what is the correct movement technique?

1. Rotate it 90 degrees

2. Twist slightly

3. Raise straight upward

4. Lift and drop

The correct answer is: Raise straight upward

When raising the slump mold, the correct technique involves lifting it straight upward. This method is essential to ensure that the concrete retains its shape and consistency after being formed. By lifting the mold directly upward, you minimize the risk of disturbing or changing the structure of the concrete mix inside the mold. This technique helps to avoid any premature collapse or misalignment of the concrete, leading to a more accurate measurement of the slump. Additionally, maintaining a straight upward movement prevents slumping or shifting of the concrete that could occur with twisting or turning motions, which may inadvertently alter the results you are observing. In contrast, other methods such as twisting slightly or rotating the mold can introduce complications, as these movements may cause the concrete to lose its shape or cause a change in the slump measurement. Lifting and dropping is also not appropriate, as this action can disrupt the settled concrete and affect accuracy as well.