ACI Certification Practice Exam

What tool is primarily used for tapping the sides of the slump mold?

1. Hammer

2. Pry bar

3. Tamping rod

4. Sledgehammer

The correct answer is: Tamping rod

The primary tool used for tapping the sides of the slump mold during the slump test is a tamping rod. This tool is specifically designed for this purpose, being a smooth, rounded, and typically metal rod that allows for even and controlled tapping on the mold. The consistency of the taps is important as it helps to eliminate air pockets that might affect the slump measurement. Using a tamping rod ensures that the sides of the mold are sufficiently vibrated, which aids in achieving an accurate measurement of the concrete's workability. This procedure is critical in assessing the flow characteristics of the concrete mix, directly influencing the reliability of the test results. Other tools like a hammer or sledgehammer are not suitable for this task because they may provide an uncontrolled force that could alter the integrity of the mold or the concrete itself. A pry bar is also not applicable in this context as it is generally used for levering or pulling rather than providing the specific tapping required during the slump test.