ACI Concrete Strength Testing Technician Practice Test

If a fracture occurs at a capped section, what should be included in calculations?

1. The thickness of the cap

2. The diameter of the specimen

3. The weight of the specimen

4. The type of cap used

The correct answer is: The thickness of the cap

When assessing a fracture that occurs at a capped section of a concrete specimen, it is crucial to include the thickness of the cap in calculations. This is because the cap influences the stress distribution at the point of fracture and significantly affects the measured strength of the concrete sample. The thickness of the cap can alter how the load is transferred from the testing apparatus to the specimen itself. If the cap is too thick or too thin, it can change the effective area of the specimen under load, leading to incorrect strength calculations. Evaluating the thickness is essential for interpreting test results accurately and ensuring that the data reflects the true behavior of the concrete. Considering the other factors—such as the diameter of the specimen, the weight, or the type of cap used—while they may be relevant in different contexts, they don't directly relate to the immediate effects of a fracture at the capped section regarding load distribution and stress concentration. Thus, for the context of fracture analysis at the capped section, the thickness of the cap stands out as the critical measurement to include in calculations.