Measurements of air-filled porosity in unsaturated organic matrices using a pycnometer

Air-filled porosity measurements for unsaturated organic matrices were made over three particle sizes and several moisture contents using a pycnometer. The reliability of the pycnometer was validated using glass beads and an uncertainty analysis was performed to assess how uncertainty in measuring the compression chamber pressure, or uncertainty in measuring sample and compression volumes, influenced the uncertainty in measuring air-filled porosity. Measured values of the air-filled porosity ( a) for glass beads obtained with the pycnometer agreed to within 1.5–2.5% of the values estimated from the glass beadʹs diameter and density. The uncertainty analysis showed that a 1% uncertainty in the volume of the compression chamber or the sample chamber led to a 1% uncertainty in the air-filled porosity, while a 1% uncertainty in the measurement of the compression chamber pressure translated into a 3% uncertainty in the air-filled porosity. In addition, the linear behavior that one would expect to see between a and dry-basis moisture content was confirmed by the measurements obtained with the pycnometer. The pycnometer proved to be a quick and accurate device for measuring air-filled porosity of unsaturated organic matrices.