Effect of Sheep Wool Fibers on Thermal Insulation and Mechanical Properties of Cement-Based Composites

The use of sheep wool as a filler of cement in order to produce mortar or plaster involves several advantages for environment and energy. Moreover, it is considered as a waste and, therefore, its use is characterized by low cost. The aim of this paper is to evaluate the influence of wool fibers on thermal conductivity and mechanical properties of cement. The samples were prepared using wool fibers, obtained from a breed of Sicilian sheep, with three different lengths (i.e., 1, 6, and 20 mm). Furthermore, in order to evaluate the influence of fiber content, the samples were prepared by varying the fiber weight fraction. The thermal conductivity of the samples was analyzed by using a heat flow meter, whereas the mechanical behavior was studied through compressive tests. In order to validate the thermal measurements, on the experimental data, two theoretical models were applied. The experimental results showed that wool fibers can be used within cementitious matrices to obtain mortars or plasters with enhanced thermal insulation properties. Nevertheless, noticeable decrements in the compressive strength are also found. Therefore, it is needed to find a compromise between these two aspects.