retentiemaat

The retentiemaat is a metric used in porous materials research to quantify how much liquid a material retains after a standard drainage procedure. It is typically defined as the ratio of the volume of liquid left in the pore space after drainage to the total pore volume (or as a percentage of the saturated liquid initially present), yielding a dimensionless value between 0 and 1 (or 0–100%).

Measurement is performed by fully saturating a specimen with a test liquid, then allowing drainage under a controlled condition (gravity, with or without applied pressure) for a defined time, and quantifying the remaining liquid by mass or volume. Calculation can be done either via volumes (V_retained / V_pore) or via masses (m_retained / m_saturated), using sample porosity or pore volume determined separately.

Applications of the retentiemaat span several fields. In soil science, it is related to concepts such as field capacity and water holding capacity. In textiles and paper, it helps evaluate moisture retention and texture stability. In construction materials, it aids assessment of dampness risk and long-term durability. The metric supports material selection, quality control, and process optimization for irrigation scheduling, drying procedures, and product performance.

Limitations and notes: results depend on the test liquid, temperature, pressure, sample orientation, and preconditioning; values are not universal constants and should be reported with method details. It is often used in conjunction with capillary retention curves and sorption isotherms. Etymology: from Dutch retentie (retention) and maat (measure).