ACI Concrete Strength Testing Technician Practice Test

When is the proper timing to conduct compression tests on moist-cured specimens?

1. As soon as practicable

2. After three days of removal

3. After twelve hours

4. Only after two days

The correct answer is: As soon as practicable

Conducting compression tests on moist-cured specimens as soon as practicable aligns with best practices in concrete strength testing. The rationale is grounded in the need to evaluate the concrete's strength while it is still in its optimal curing phase. The internal hydration of the cement paste continues for an extended period after casting, so testing should be done while the specimen retains adequate moisture. Testing too early can lead to inaccurate results due to insufficient strength development, while waiting too long may result in variations in strength because of environmental factors or drying out. Therefore, the guideline for compression testing is to perform it as soon as is realistically feasible after the specified curing period—typically between 24 hours to several days—ensuring that the concrete is in a state where it can provide a reliable indication of its strength characteristics. This approach helps technicians assess the structural integrity of concrete accurately and ensures that any potential issues can be addressed during the construction process.