Organized Framework of Main Possible Applications of Sheep Wool Fibers in Building Components

Abstract

Greasy sheep wool is currently considered a special waste for its high bacterial load, with expensive disposal costs for sheep breeders. For this reason, wool is often burned or buried, with serious consequences for the environment. On the other hand, sheep wool is well regarded as one of the most performative insulating natural fibers due to its thermo-hygrometric and acoustic properties. In the building sector, sheep wool meets the requirements of green building components because it is an eco-friendly material, there is a surplus of it, it is annually renewable, and totally recyclable. If used instead of common insulation materials (e.g., fiberglass, rock wool, polyurethane foam, polystyrene), sheep wool offers significant benefits for sustainability such as a reduction in the production costs for new insulating materials and in environmental pollution. Mechanical and physical properties of sheep wool investigated in previous studies were assessed and discussed with the aim of providing an organized framework of possible applications of wool fibers in building components. This paper highlights in detail aspects that have not yet been investigated enough to detect new potential uses of sheep wool fibers in rural buildings and the reuse of traditional ones.

Wool-Reinforced Cement Based Composites

“…The scouring water (at 65 °C) does not dissolve the wax (i.e., lanolin), and a detergent is added to remove the dirt Figure 2. SEM image of (a) sheep's wool fibre showing its surface scales [30] (CC BY 4.0, 2020, Sustainability), and (b) man-made synthetic smooth glass fibre [38] (BY-NC-ND 3.0, 2017, E-Polymers).…”

“…The sheep wool is an eco-friendly material, annually renewable, and totally recyclable which meets the requirements of green building components and therefore it is increasingly used in the building materials technology [30]. Also, the wool fibres are non-flammable.…”

“…Sheep wool is regarded as one of the most performative insulating natural materials due to its thermo-hygrometric and acoustic properties [22,30,43,47,48]. One of the most important factors concerning the thermal insulation is thermal conductivity of material.…”

“…Despite all the above-mentioned benefits, the large-scale production of cement-based composites reinforced with sheep wool fibres is currently limited by the long-term durability [29]. However, in all the previous researches, including the recent review papers by Parlato and Porto [30] and Allafi et al [31], there is no information on the durability of cement-based composites with the addition of wool fibres.…”

“…To mitigate the degradation of wool fibres in cement-based composites, two main methods have been adopted: fibre pre-treatment or cement matrix modification. Attempts have been made to modify the surface of the fibres to improve their mechanical properties and durability [30,32,33], and to reduce concrete's alkalinity by partially replacing the cement with supplementary cementitious materials [34], or use blended cement [35] and/or low-alkali cement [29].…”