Influence of Cement Type and Curing Conditions on the Flexural Strength and Microstructure of Mortars Reinforced with Sheep Wool Fibers

Various types of dispersed reinforcement in the form of thin fibers are known to improve the toughness of cement-based materials. In cement-matrix composites, the application of sheep wool, which is an ecological material, annually renewable and completely recyclable, perfectly fits into green and sustainable development. As the wool tends to be damaged by alkaline environment, this paper describes the influence of the cement type on the performances of sheep wool reinforced mortars. Hence, ordinary Portland cement (CEM I 42.5R), limestone Portland cement (CEM II/B-LL 42.5R), and calcium sulfoaluminate cement (SL05 42.5) are analyzed. The latter is known to be low carbon compared to CEM I. Additionally, two conditions, differing on maturity in high or low humidity, at constant temperature of 20°C, are used to cure the specimens. As a result, mechanical properties, and flexural toughness in particular, strongly depend on the type of cement and on the curing conditions. This is true both for the mortar specimens reinforced with sheep wool fibers and for those reinforced with polypropylene fibers, herein considered as reference fibers. © 2022 American Concrete Institute.