ACI Concrete Field Testing Technician - Grade I Practice Exam

What shape is the mold used for the slump test?

1. Square prism

2. Frustum of a cone

3. Cylinder

4. Rectangle

The correct answer is: Frustum of a cone

The mold used for the slump test is indeed shaped like a frustum of a cone. This design is crucial because the frustum shape allows for the measurement of the concrete's consistency and flowability once the mold is removed. When concrete is placed into the frustum-shaped mold and then lifted, the shape aids in observing how much the concrete slumps or settles under its own weight, providing vital information on its workability. This specific shape also helps to ensure that the concrete test results are consistent and reliable, as the geometry influences how the concrete behaves during the test. Understanding this is important for ensuring proper testing procedures and accurate results in concrete quality assessment.