For coarse aggregate testing, which sieve size is recommended to avoid the potential for overloading?

For coarse aggregate testing, which sieve size is recommended to avoid the potential for overloading?

• A. Sieves larger than 203.2 mm diameter
• B. Sieve smaller than 203.2 mm diameter
• C. Exactly 203.2 mm diameter
• D. Any sieve size is acceptable

Answer: (A)

When testing coarse aggregates with sieves, the goal is for the material to pass through the openings smoothly during agitation. If the sieve opening is too small for the largest particles, they can pile up and clog the screen, causing overloading and inaccurate size distribution. Using a sieve with an opening larger than the largest particles in the sample gives a margin that lets material move freely and prevents bridging or packing on the screen. That’s why selecting sieves larger than 203.2 mm diameter is the best practice. A smaller sieve would be more prone to overloading, an opening exactly at 203.2 mm may still be borderline for some samples, and saying any size is acceptable ignores the need to accommodate the material.

When testing coarse aggregates with sieves, the goal is for the material to pass through the openings smoothly during agitation. If the sieve opening is too small for the largest particles, they can pile up and clog the screen, causing overloading and inaccurate size distribution. Using a sieve with an opening larger than the largest particles in the sample gives a margin that lets material move freely and prevents bridging or packing on the screen. That’s why selecting sieves larger than 203.2 mm diameter is the best practice. A smaller sieve would be more prone to overloading, an opening exactly at 203.2 mm may still be borderline for some samples, and saying any size is acceptable ignores the need to accommodate the material.