ACI Concrete Field Testing Technician - Grade I Practice Exam

Before lifting the slump mold, what surrounding area must be cleared of concrete?

1. The area above the mold

2. The area surrounding the base of the mold

3. The area below the bottom of the mold

4. The sides of the mold

The correct answer is: The area surrounding the base of the mold

Before lifting the slump mold, it is essential to ensure that the area surrounding the base of the mold is cleared of concrete. This is crucial for several reasons. First, clearing the area around the base allows for an accurate reading of the slump. If concrete is present around the base, it can affect the measurement by potentially lifting the mold unevenly or creating resistance that alters the flow of the concrete when the mold is removed. Proper measurement is vital to assessing the workability of the concrete mix. Second, a clear area ensures safety during the lift. If there is concrete or debris around the mold, it can pose a tripping hazard or lead to spills, undermining the integrity of the slump test process. Ensuring that nothing obstructs the mold’s base contributes to the reliability of the test results—an essential factor when evaluating concrete consistency and quality.