Which scenario would require a contractor to take core samples?

The requirement for a contractor to take core samples is primarily driven by the need to ensure compliance with material quality standards, particularly when there are indications that the materials may not meet the specified criteria. In this case, if a core sample shows values that are more than 2.0 percent below the average, it suggests a potential quality issue that needs to be investigated further. By taking core samples, the contractor can assess the consistency and quality of the materials in question, thereby verifying whether they meet the project specifications or if corrective actions are necessary.

This practice is aligned with quality management systems, as it emphasizes the importance of monitoring and verifying material performance against defined standards. If core samples reveal significant deviations from the average, it highlights a critical point where detailed evaluation is warranted, ensuring that the materials used in construction are reliable and within the required parameters.