ACI Concrete Field Testing Technician - Grade I Practice Exam

What is the required number of strokes of the tamping rod for consolidating each layer in a 0.5 ft³ measure?

1. 10

2. 15

3. 25

4. 30

The correct answer is: 25

The correct answer for the required number of strokes of the tamping rod for consolidating each layer in a 0.5 ft³ measure is based on standard procedures outlined in concrete testing guidelines. When consolidating concrete in a measure of this size, it is essential to ensure that the concrete is adequately compacted to avoid air pockets and achieve the desired density. For a 0.5 ft³ measure, the industry standard dictates using 25 strokes of the tamping rod for each layer. This number of strokes is determined through specific testing practices established by organizations such as ASTM (American Society for Testing and Materials). The strokes should be applied uniformly and at an appropriate angle to ensure that the concrete is uniformly compacted throughout the measure. This process of consolidation is crucial, as it directly impacts the accuracy of the test results and the strength characteristics of the concrete. Properly consolidating the concrete ensures that the test sample accurately represents the batch of concrete being evaluated. Therefore, 25 strokes are required to achieve the necessary consolidation for each layer in this context.