How long should shaking a sample for gradation verification last?

Shaking a sample for gradation verification is a critical step in ensuring the accurate determination of the particle size distribution of the aggregate material. The correct duration for this shaking process is 1 minute. This time frame is established based on best practices that balance the need for thorough mixing of the sample without excessive degradation of the finer particles.

Shaking for 1 minute allows sufficient time for the particles to separate and settle into their respective sieves, thus providing reliable and reproducible results. This duration ensures that the sample is adequately representative of the material being tested while maintaining the integrity of the various sizes present.

Longer durations might lead to excessive breakdown of finer aggregates, which can skew the results. Conversely, shorter shaking times would not provide enough time for proper stratification of particle sizes, resulting in inaccuracies in the gradation results. Thus, 1 minute is the optimal time frame for this process.