Durability Assessment of Compressed Earth Bricks (CEB) Incorporating Raw and Treated Red Algae "Gelidium Sesquipedale" Fibers

A number of research works focus on the mechanical and hygrothermal properties of earth-based materials. However, the durability of this type of material – especially compressed-earth bricks – is a major concern, and it is essential to improve their durability if they are to be adopted widely in construction. The main objective of this work is to evaluate the durability of compressed-earth bricks (CEBs) reinforced with raw and treated algae fibers; in the latter case, having undergone two treatments: alkaline treatment with sodium bicarbonate, and double coating treatment (using linseed oil and metakaolin). Raw and treated algae fibers were incorporated into CEBs at an addition ratio of 1.5% by weight. Durability tests were carried out, corresponding to weathering or occupant actions: a wet erosion test to simulate rain or accidental water droplets, and a contact test to assess the reaction of CEBs to moisture absorption in conditions that simulate the application of a mortar joint. In addition, dry abrasion resistances were evaluated. Compared to the unreinforced CEBs, the results show that the addition of raw and treated fibers to CEBs increased both wet erosion and dry abrasion resistance. Moreover, the CEBs reinforced with treated algae fibers showed fewer visible cracks than those reinforced with raw fibers after completion of the contact test. This may be due to the treatments undergone by the fibers, which have reduced their water-absorption capacity, thus inhibiting widespread crack formation on the surface of the bricks.