ACI Concrete Field Testing Technician - Grade I Practice Exam

If the concrete contains aggregate larger than the maximum allowed for this test, how must the sample be processed?

1. Soaked and weighed

2. Dried and crushed

3. Wet sieved over a 1 1/2 in. (37.5 mm) sieve

4. Air dried and ground

The correct answer is: Wet sieved over a 1 1/2 in. (37.5 mm) sieve

When dealing with concrete that contains aggregate larger than the maximum size allowed for a specific test, wet sieving is the appropriate method to ensure that only the allowable aggregate size is used in the sample. Wet sieving allows for the separation of the larger particles from the finer aggregates, which is critical for accurate testing results. By using a 1 1/2 in. (37.5 mm) sieve, any oversized aggregate can be properly removed from the sample, facilitating a test that is compliant with the standards for concrete that will yield valid and reliable data. Soaking, drying, or crushing the aggregate would not appropriately address the issue of oversized particles within the context of the test requirements. These methods do not inherently filter out larger aggregates, which is necessary to achieve a sample suitable for testing. Wet sieving specifically addresses the need to obtain a sample with the correct particle size distribution, ensuring the integrity of the test results.