5.3 : ふるい分析と粒度曲線

Sieve analysis of aggregates is carried out using a set of sieves stacked in descending order of their aperture size from top to bottom.

 The sizes of sieves vary for coarse aggregates and fine aggregates.

A sample of air-dried aggregates is weighed and sieved through the sieves either by shaking them mechanically or manually for a specified time.

In the process, each sieve retains particles coarser than its mesh size while allowing finer particles to pass through to the next sieve.

The weight of fractions retained on each sieve is recorded, expressed as the percentage of the total mass, and represented in a table.

Starting from the finest sieve and moving upward, the cumulative percentage passing each sieve is calculated and rounded to the nearest one percent.

Further, a semi-logarithmic graph is used to represent the passing percentage on the y  axis and sieve apertures on the logarithmically scaled x axis.

On this graph, the cumulative passing percentage corresponding to each sieve size is plotted to obtain the grading curve, which indicates the distribution of aggregate particles based on their sizes.