The use of wool as fiber-reinforcement in cement-based mortar

As the mechanical response is better than in plain cement-based mortars, fiber-reinforced mortars are widely used in the construction industry. Specifically, the fracture toughness in tension increases with the volume and the aspect ratio (i.e., the ratio between length and diameter) of the fibers, which are generally made with polymeric (e.g., polyethylene, polyvinylchloride, etc.) or inorganic (e.g., glass, carbon, etc.) materials, or with steel. However, some vegetal fibers, such as bamboo and hemp, have been also introduced in the last decades. To produce new mortars with animal fibers, the use of wool as fiber-reinforcement is investigated for the first time in the present paper. According to UNI EN 196-1-2006, three point bending tests have been performed on three series of beams: plain mortar, mortar reinforced with 1% in volume of wool, and mortar reinforced with 1% in volume of treated wool. In the latter case, wool is previously treated with atmospheric plasma in order to modify the nano-metric properties of the fiber surface. As a result, both the flexural strength and the ductility increase when wool, plain or treated, is added to cementitious mortars. In other words, wool does improve the mechanical and ecological performances of cementitious mortars and creates a link between textile and construction markets.