Porosity Analysis

4.3 Thermal conductivity evolution with porosity

The total porosity decreased with increasing compaction pressure, with values of 37.1 %, 31.9 %, 30.9 %, and 29.4 % for compaction pressures of 0, 2.5, 5.0, and 7.5 MPa, respectively.

Table 3 Porosity fraction in open air environment.

The porosity analysis, presented in Table 3, indicates that the highest porosity is found in the reference samples and decreases as the remelting power increases.

Some small pores are visible in the intermediate space of the nanosized particle fragments. This is a typical behavior when irregularly shaped grains are stacked.

Porosity analysis considered BSE images at five different positions on each sample: the images were binarized (see Fig. S3), and the averaged porosity data are summarized in Table 2.

As expected from the results of increased linear shrinkage and decreased porosity, the increasing interconnectedness of soil particles contributed to a decrease in the samples' CTE