ACI Concrete Field Testing Technician - Grade I Practice Exam

What is the maximum allowable deviation for a supporting surface's level where specimens are stored?

1. 1/2 in. per ft.

2. 1/4 in. per ft.

3. 1/8 in. per ft.

4. No deviation allowed

The correct answer is: 1/4 in. per ft.

The maximum allowable deviation for a supporting surface's level where specimens are stored is set at 1/4 inch per foot. This standard is critical to ensure that concrete specimens are not subjected to untoward stresses that may arise from improper support, which can lead to inaccurate test results. A level surface facilitates uniform curing and consolidates the integrity of the specimens, promoting consistent and reliable testing outcomes. Setting the maximum deviation at 1/4 inch per foot strikes a balance between practical tolerances in construction and the need for precision in concrete testing. If the deviation were tighter, such as 1/8 inch per foot, it could introduce unnecessary complications in the placement and handling of forms or molds. Conversely, allowing a larger deviation may compromise the quality and reliability of the results, as uneven surfaces could distort the specimens' shape or lead to defects. The other options either set parameters that are too strict or too lenient for practical applications in the field, thus highlighting the importance of adhering to the established standard of 1/4 inch per foot for specimen storage.