Splitting tensile strength of cement-stabilized and face mask fiber-reinforced sand

The tendency towards reinforcement of cement-treated sands with inclusion of fibers has increased in recent years. This is due to the fact that fibers reduce the brittle behavior and improve the mechanical properties of the sandy soil samples. Since 2019, because of the epidemic of coronavirus, the use of disposable face masks has become increasingly popular among the public to the extent that their burial, reproduction and reuse have become one of the major environmental problems. Therefore, in this research, an attempt has been made to reuse the mask fibers in the application of cement-reinforced sands. In this regard, samples with 2, 4, 6 and 8% cement contents, reinforced with different amounts of fibers (0, 0.25, 0.5 and 0.75%) in different relative densities (35%, 50%, and 70% sand) were prepared. After seven days of curing, the stabilized/reinforced specimens were subjected to a comprehensive series of Brazilian tensile splitting tests. Based on the results of these experiments, the synergetic influence of cement and mask fiber additives as well as the contribution of relative densities on the tensile strength parameters The results showed that the addition of cement percentage and increasing relative density have a significant effect on improving the tensile strength index of cement sands. The percentage of mask fibers 0.25% is the optimal amount of added fibers (the maximum tensile strength in this percentage of fibers). The key parameter (the ratio of porosity to cement content) definition and several empirical relations for estimating the tensile strength of reinforced and reinforced samples with very good accuracy are presented and the optimal percentages of mask fibers are suggested. Finally, it was observed that the use of fibers, especially in a cemented mixture, has highly positive effects on the tensile behavior of the samples by correcting the failure properties. Using disposable mask fibers instead of conventional fibers can substantially reduce disposal costs and environmental pollutions.