dryvolume

Dryvolume is a term used in materials science, geotechnical engineering, and related fields to describe the volume occupied by the solid constituents of a material when it is dry, i.e., excluding pore space and moisture. It is distinct from bulk volume, which includes voids, and from wet volume, which includes absorbed liquids or moisture.

Measurement and calculation of dryvolume can be approached in several ways. One common method is to compute it from mass and true density: dryvolume = mass_dry / true_density, where true density is the density of the solid material itself (not including pores). True density can be measured by gas pycnometry or similar methods. Alternatively, if the bulk volume and porosity are known, dryvolume can be obtained as dryvolume = bulk_volume × (1 − porosity).

Relationships to other properties are central. Dryvolume is linked to dry density (mass of dry solids per unit dryvolume) and to porosity (the fraction of bulk volume that is void). In soils and powders, the distinction between dryvolume and bulk volume underpins calculations for compaction, compaction testing, and material handling.

Applications include soil science for estimating dry density and compaction, ceramics and powders where the green (dry) density matters before sintering, and concrete mix design where the volume of dry constituents is distinguished from the poured volume after water addition. A representative example: a dry soil sample with mass 2.0 g and true density 2.65 g/cm³ yields a dry volume of about 0.755 cm³.

Notes: usage of the term is not universally standardized; definitions may vary by discipline. See also bulk density, porosity, true density, and pycnometry.