granulometrie

Granulometrie, or granulometry in English, is the study of the size distribution of particles within a granular material. It quantifies the proportion of particles across a range of sizes, usually shown as a grain size distribution curve or as percent passing selected size thresholds. This information informs properties such as strength, permeability, density, and workability.

Common methods range from sieve analysis for coarser materials to sedimentation or laser-based techniques for finer fractions. Sieve analysis uses a stack of sieves with decreasing openings; after agitation, the mass retained on each sieve yields percent retained or percent passing. Wet sieving is used for clays to prevent agglomeration. For fines, sedimentation methods (hydrometer or pipette) estimate the PSD from settling rates; laser diffraction covers wide size ranges; imaging can extract PSD from micrographs.

From the PSD, statistics such as d10, d50 (median), and d90 are reported. In soil engineering, indices include the uniformity coefficient Cu = D60/D10 and the curvature Cc = (D30)^2/(D10×D60). The granulometrie influences compaction, permeability, strength, and durability of materials, as well as the behavior of mixtures such as concrete aggregates or soils in contact with water.

Applications span geotechnical engineering, construction materials, mining, ceramics, pharmaceuticals, and environmental science, where granulometry affects filtration, separation, and process design. Results are typically presented as cumulative percent passing versus particle size and compared with standards or material specifications.