Mechanical properties of high-strength cement mortar including silica fume and reinforced with single and hybrid fibers

Abstract The special mechanical properties and cost-effectiveness of cement-based mortar make it a good material to be used in the rehabilitation and maintenance of structures. In such usage, the production of high-strength mortar (HSM) reinforced with fibers is highly required for enhancing the mechanical properties and extending the service life of mortar. Therefore, the study examined the optimal fiber content for a case study of HSM incorporating silica fume and reinforced with mono/hybrid steel and polypropylene fibers (PPFs). Thirteen mixes with different fiber volume fractions of mono/hybrid steel and PPFs were designed in the current study. The impact of the fiber content was evaluated based on flowability, compressive strength, splitting tensile strength, flexural strength, ultrasonic pulse velocity, and water absorption. The results show that both steel and PPFs have a negative effect on the flowability of tested HSM mixes. Regarding the investigation properties of HSM mixes, the results show that incorporating steel fibers improves the properties of HSM, in particular the content of 1.25%, while the addition of PPFs has little effect. It is also noted that in the case of incorporating hybrid fibers into HSM mixes, it is found that the improvement of properties existed for the HSM mix with a hybrid fiber of 1.3% steel fibers and 0.2% PPFs.