Synergistic effects of modified sheep wool fibers on impact resistance and strength properties of concrete composites

Sheep wool is a fiber composite material derived from natural renewable sources. Natural fibers are becoming more popular in various applications, including the building industry. The reason for such popularity is because of the emergence of environmental, ecological, and economic concerns. Another reason is due to the favorable characteristics of natural fiber such as biodegradability, nontoxicity, combustibility, ease of availability, non-abrasiveness, light weight, low cost, and high corrosion resistance. Despite these benefits, natural fibers have certain disadvantages, such as high water sensitivity, low melting temperature, and poor adherence to other materials. In this regard, the surface modification of natural fibers has attracted the attention of researchers to overcome these limitations. The impact resistance and strength properties of conventional (WF) and modified (MWF) waste sheep wool fibers in the manufacturing of concrete composites were examined in this study. WF fibers were used in five concrete mixtures, ranging from 0.5 to 2.5%. Pre-treatment was applied to the sheep wool fibers in five concrete mixtures with the same fiber content, and the results were results were examined with reference to a controlled plain concrete mixture. The addition of WF and MWF to concrete mixtures marginally reduced the compressive strength. However, the positive interaction between wool fibers and the cement matrix increased the tensile strength and impact resistance, resulting in increased concrete ductility and energy absorption capacity. The results show that pretreatment of sheep wool fibers significantly improves the performance of wool-fiber-reinforced concrete under impact loads. Consequently, one of the most promising building materials for environmentally friendly construction is wool-reinforced cement-based composite.