Reuse of livestock waste for the reinforcement of rammed-earth materials: investigation on mechanical performances

Agricultural wastes as additive within raw earth materials could both improve mechanical and physical properties of new sustainable construction materials and enhance waste management in a circular economy perspective. This study intends to fill the lack of knowledge considering the mechanical effects of animal fibers on rammed earth materials. The effects of a livestock waste, i.e., sheep wool fiber (SWF), as reinforcing element in building components produced by using raw earth and lime-free mortars, have been evaluated. Linear shrinkage, flexural strength, and compressive strength were evaluated on samples incorporating SWF, with the aim of assessing the effects of this waste addition on the mechanical performances of a new bio-composite material. The samples were made by varying the content of wool (0.25 % or 0.50%weight) and the length of the fibers (from 10 mm to 40 mm). The best result of the flexural strength was 1.06 MPa, exhibited by samples made with the longest and highest percentage of fibers, 40 mm and 0.50%, respectively. The addition of SWF to adobe bricks changed their failure mode, from fragile to ductile, reduced dry density and shrinkage rate.