ACI Certification Practice Exam

What is a required step before testing a sample of concrete containing large aggregates?

1. Let it sit

2. Skip testing

3. Wet sieve the sample

4. Dry it thoroughly

The correct answer is: Wet sieve the sample

The correct answer involves the process of wet sieving the sample. When dealing with concrete that contains large aggregates, it's crucial to ensure that the aggregates are evenly distributed and separated during testing for accuracy. Wet sieving helps to eliminate the issues that can arise from dry sieving, such as the particles sticking together or dust affecting the results. By using water during the sieving process, larger aggregates can be effectively separated from the finer materials without losing any sample, which ensures that the test accurately reflects the concrete's true composition. Wet sieving also helps limit the amount of fines that might pass through the sieve unintentionally, allowing for a more precise measurement of aggregate sizes and proportions. On the other hand, allowing a concrete sample to sit or drying it thoroughly would not address the issue of effective separation of large aggregates during testing. Skipping the testing process altogether would not provide any valuable information about the concrete's properties or performance. Therefore, wet sieving is an essential step before conducting any tests on samples containing large aggregates to ensure the integrity and reliability of the testing process.