13.3 : 디자인 예시: 집계 그라데이션

The manager of a concrete plant needs to choose between two manufactured sand production facilities, A and B, to purchase sand that meets the required gradation for use in concrete.

Samples of manufactured sand from the conveyor belts at both facilities are collected after halting the belts.

Two templates are spaced and inserted into the sand stream.

The complete material in the space between the template is transferred into a container.

This is repeated at two more random locations on the belt.

The collected samples are then mixed to form a representative sample, labeled, and kept in an oven to dry.

The dried samples are split using a sand splitter into equal portions, which are then subjected to sieve analysis by passing through a set of standard sieves.

The corresponding gradation curve is plotted.

The gradation curve for the sand from facility A is observed to be within the region bound by the prescribed limits as per the concrete mix design.

Contrarily, the sand from facility B falls outside this region. As a result, the manager decides to buy sand manufactured at facility A.