ACI Concrete Field Testing Technician - Grade I Practice Exam

What is the minimum outside diameter of the vibrating element used in the slump test?

1. 0.50 in. [13 mm]

2. 0.75 in. [19 mm]

3. 1.00 in. [25 mm]

4. 1.25 in. [32 mm]

The correct answer is: 0.75 in. [19 mm]

The minimum outside diameter of the vibrating element used in the slump test is 0.75 inches [19 mm]. This specification is critical in ensuring that the device is sufficiently sized to provide accurate and consistent results when measuring the consistency of fresh concrete. A vibrating element with the appropriate diameter allows for effective engagement with the concrete sample, thus contributing to reliable test outcomes. Using a smaller diameter vibrating element could lead to inadequate vibration effects on the concrete, potentially impacting the test results and the overall assessment of the mix's workability. Ensuring that the vibrating element meets this minimum size requirement is part of the standard procedures to maintain uniformity and reliability in concrete testing.