korrelmaten

Korrelmaten are measurements used to describe the grain size distribution of a particulate material, such as soil, sediment, powder, or aggregate. They provide a concise numerical profile of how particle diameters are spread across a sample and are essential for applications in geology, civil engineering, materials science, and pharmaceuticals. Commonly used descriptors include mean grain size, the median (D50), and other percentiles such as D10 and D90, which indicate the particle sizes at which 10% and 90% of the sample are finer, respectively. Additional metrics include sorting (a measure of dispersion), skewness, and sometimes kurtosis. In practice, grain-size data are often represented on a phi scale, where phi is the negative logarithm of the particle diameter, which helps to linearize log-normal distributions frequently observed in natural materials.

Measurement methods vary with the size range of the particles. Sieve analysis is standard for coarser grains (typically larger than about 0.063 millimeters). For finer materials, methods such as laser diffraction, sedimentation (Stokes’ law-based approaches), and image analysis of micrographs can be used. Techniques like dynamic light scattering and electron microscopy may be applied for sub-micron particles. The choice of method and sampling procedure must consider representativeness, moisture content, and the potential for particle breakage or aggregation.

Korrelmaten are used in design and quality control, for example in forecasting soil behavior, selecting aggregates for concrete, controlling powder flow in manufacturing, and interpreting sediment transport and depositional processes. They are related to the broader concept of particle-size distributions and are often complemented by statistics such as the geometric mean, standard deviation, and distribution shape.