ACI Certification Practice Exam

The correct answer is that two or more portions should be collected from a revolving drum truck for sampling. This is essential because collecting a single portion may not provide a representative sample of the entire load. The variability in materials during mixing can lead to inconsistencies, and by taking two or more portions, you can achieve a more accurate and reliable assessment of the material's properties.

Sampling in this manner allows for the averaging of different segments of the load, which helps to account for any discrepancies that may exist due to segregation or uneven mixing. This practice is aligned with standard sampling procedures in material testing, ensuring that the sample represents the overall quality of the material being delivered.

Collecting just one portion does not allow for the detection of any variations or inconsistencies within the batch. Therefore, to ensure that testing results are valid and reflective of the entire haul, the practice of taking at least two portions is recommended and crucial in quality control processes.