Aiming to reduce the resources invested in the laboratory assessment of unfired clay bricks incorporating natural wastes as additives, this paper proposes an evaluation of the surface porosity of unfired clay bricks with almond husk powder using processing of the SEM (Scanning electron microscope) images of representative cubes and its relationship with the bricks’ strength. Used clay is extracted from Bensmim red soil in Ifrane – Morocco and determined as an Illite. One control specimen with pure clay and four specimens were prepared using the proportions 2, 5, 10, and 20 wt.% of almond husk powder. After drying, SEM analysis is done on the specimens. The processing of the issued images is done using ImageJ software. The results show, in general, an increase in the surface porosity with the increase of almond husk powder in the matrix. This is reported due to the formation of coagulant volumes that generates a porous network depending on the size and the amount of the additive. However, a considerable decrease in the porosity is shown using 2 wt.% additive which is reported to the fiber bridging mechanism. The increase in the surface porosity was followed by an increase in strength. Theoretical models are evaluated for the best fit in the relationship between strength and porosity. Nevertheless, the polynomial modeling of degree 3 is considered the most adequate. The findings in this research establish a potential road to predict unfired clay bricks quality using the processing of SEM images of only representative specimens of the surface porosity.

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