When conducting a sieve analysis on dry materials, what is the essential characteristic of the particles?

When conducting a sieve analysis on dry materials, it is crucial that the particles are free from moisture. Moisture can cause the particles to clump together, which would lead to inaccurate results during the sieve analysis process. If the materials are damp, the water can create aggregates that prevent individual particles from passing through the sieve openings correctly, thus skewing the analysis of their size distribution. Dry particles, on the other hand, can be accurately assessed, allowing for a precise determination of the gradation of the material being tested.

While uniform shape, heaviness, and angularity may influence other characteristics of the particles, they are not essential for the basic understanding and proper execution of sieve analysis. The focus should primarily be on ensuring that the materials are free from moisture to maintain the integrity of the test results.