ACI Concrete Field Testing Technician - Grade I Practice Exam

If less than 2.5 pints of alcohol are used, how is the air content indicated?

1. It is always indicated by the final meter reading

2. Only by visual inspection

3. By the temperature of the solution

4. The number of calibrated cups of water must be adjusted

The correct answer is: The number of calibrated cups of water must be adjusted

The indication of air content in a concrete mix depends on the amount of alcohol used in the test procedure. When the volume of alcohol is less than 2.5 pints, adjustments become necessary to ensure accurate measurements. In this context, the number of calibrated cups of water that are used in the test must be adjusted accordingly to compensate for the lower volume of alcohol. This adjustment is essential because the air content measurement relies on achieving a consistent relationship between the alcohol and water volumes in the test apparatus. By modifying the number of calibrated cups of water, the technician can maintain the integrity of the test results despite the reduced alcohol volume. Other options may refer to alternative methods or indicators of air content, such as meter readings, visual checks, or temperature measurements, but they do not directly address the necessary adjustments to the testing setup based on alcohol volume. Therefore, they are not applicable in this scenario.