ACI Certification Practice Exam

What occurs if the slump test sample shears off on one side?

1. The sample is valid

2. The test should be ignored

3. The technician must record it

4. The sample should be retested

The correct answer is: The sample should be retested

When a slump test sample shears off on one side, it indicates that the sample is not stable and might not provide an accurate representation of the concrete's workability. This shearing can be the result of various factors, including improper sampling methods, adverse weather conditions, or the nature of the concrete mix itself. In such cases, the test sample's integrity is compromised, meaning that the results obtained from that test may not reliably reflect the characteristics of the concrete. Therefore, to ensure accurate testing and reliable results, it is necessary to retest the sample. Retesting allows for another opportunity to assess the workability of the concrete under typical conditions, leading to more dependable data for quality assurance and control purposes. Recording the shearing or any anomalies is important but does not replace the need to retest, since the primary goal is to obtain a valid slump measurement that accurately represents the concrete's performance. Thus, retesting the sample is the appropriate action to take in this scenario.