REFINING POROSITY ANALYSIS IN HIGH-STRENGTH MICROCONCRETES THROUGH MANUAL THRESHOLD SEGMENTATION IN X-RAY MICROTOMOGRAPHY

The present study aimed to assess the effectiveness of the image segmentation technique utilizing the Threshold method for the measurement of porosity in high-strength microconcrete samples that incorporate metakaolin. Specifically, X-ray microtomography testing was conducted on the microconcrete samples after 7 days of curing, and the voxel size was set at 20µm. Subsequently, the images were subjected to pre-processing measures including histogram regularization and noise reduction. Thereafter, the regions of interest within the images were demarcated through segmentation, enabling the isolation of the porosity from the other phases of the microconcrete. To execute the segmentation, grayscale values were systematically adjusted via the Threshold method to elucidate the impact of such variations on the determination of porosity properties. The study findings indicate that the proposed technique yields reliable measurements of the total porosity percentage of the material, despite the human factor inherent in the manual Threshold segmentation approach. However, caution should be exercised while performing segmentation when assessing pore quantity and dimensions as these are substantially influenced by this technique.