ACI Concrete Field Testing Technician - Grade I Practice Exam

If the concrete sample contains oversized aggregate, what must be done?

1. Dry sift through a 1-inch sieve

2. Wet sieved over a 1-inch sieve

3. Crush the oversized aggregate

4. Remove oversized aggregate manually

The correct answer is: Wet sieved over a 1-inch sieve

When dealing with oversized aggregate in a concrete sample, wet sieving over a 1-inch sieve is the correct approach. This process involves using water to ensure that the finer particles of aggregate are separated effectively from the larger ones. Wet sieving prevents dust and fine particles from adhering to the larger aggregates, which can be a challenge in dry sieving methods. In this context, performing wet sieving not only helps to accurately categorize the aggregate sizes but also provides a more thorough assessment of the sample, ensuring that the proportions of the materials used in the concrete mix are precise. This is crucial for quality control and meeting project specifications. The other options, while they might seem practical at first glance, do not adequately address the requirement for proper separation and assessment of the oversized aggregate. For instance, dry sifting may not adequately clean the aggregates as moisture can help dislodge fine particles. Crushing oversized aggregates could alter their size distribution and affect the sample's integrity. Manual removal, while it can address the issue, is often impractical for larger volumes and may not ensure comprehensive removal of all oversized pieces.