The application of disposable face mask fibers in the enhancement of the mechanical properties of cement-stabilized soils is rigorously examined in this study through performing several triaxial tests on fiber-reinforced sand-cement mixtures with varying contents of additives under different confining pressures. To this end, sand samples stabilized with different percentages of cement (4% and 8%) are reinforced with various contents of face mask fibers (0%, 0.25%, 0.5% and 0.75%). After seven days of curing, the fiber-reinforced stabilized specimens are subjected to a comprehensive series of consolidated drained (CD) triaxial tests with all-round pressures of 50, 100 and 200 kPa. The results generally show that the addition of mask fibers to sand-cement mixtures up to 0.25% increases their ultimate strengths; whereas further increase of fiber content is observed to have an adverse impact on the strength parameters of the composite. Therefore, 0.25% mask fiber inclusion is reported to be the optimum content, which constitutes maximum strength characteristics of the samples. The contribution of mask fiber addition to the variation of ultimate strength of stabilized mixtures is noticed to be more pronounced in the samples with higher cement contents under greater isotropic confining pressures. Moreover, with increasing the percentage of mask fibers, the failure strain of all stabilized samples increases, thus exhibiting more ductile behavior. Unlike for the samples containing relatively low cement contents (4% herein) where brittleness index is barely affected by the mask fiber content, this parameter significantly decreases with the fiber inclusion for the specimens stabilized with relatively high cement contents (8% herein). Secant modulus is also observed to experience a decreasing trend with the addition of mask fibers to the mixture; the trend which is more pronounced for samples containing higher cement contents. Finally, the internal friction angle and cohesion of cement-stabilized samples generally show increasing trends with the addition of mask fibers up to 0.25% and then reveal decrement. Overall, the combination of cementation and fiber reinforcement demonstrates a significant synergistic effect, resulting in notable improvements in the mechanical properties of fine sands.

To prevent the transmission of airborne infectious diseases (SARS, H1N1, COVID-19, and influenza), the use of disposable surgical face masks has increased dramatically in the past few years. To mitigate the environmental consequences associated with mask waste, implementing circular economy strategies with the reuse of mask waste is a sustainable method. This study explores an innovative way to reuse mask fiber (MF) with dredged sediment waste together as road construction materials. First, the MF was introduced into cement-treated/ untreated dredged marine sediment mixtures with different content and lengths. Then, a variety of laboratory tests were carried out to explore the basic physical and chemical characterization of raw materials and the development of mechanical properties of mixtures. In addition, the intrinsic mechanism of MF inclusion on cement-treated sediments was analyzed by scanning electron microscope (SEM) test. The results show that the inclusion of MF significantly improves the unconfined compression strength (UCS) and splitting tensile strength (STS) of both treated and untreated specimens. The highest UCS and STS values are at the condition with an MF content of 0.25%, a length of MF of 2 cm, and a curing time of 28 days. The combined strength increase caused by cement-MF together inclusion is much greater than the strength increase caused by either of them separately. It was also found that the elastic modulus (E50) decreased with the inclusion of MF. Furthermore, the addition of MF changes the brittle behavior of the specimens, which also improves the ductility and residual strength of the specimens. The SEM analysis demonstrates the microstructure of MF and MF-reinforced specimens. The creation of a stable and interconnected microstructure is largely attributed to the bridging impact of MF and the binding effect of hydration products, which significantly improves the mechanical behavior of specimens. The MFreinforced cement-treated sediment could be an innovative, environmentally friendly, and economical material for road construction.

This study rigorously examined the enhancement of the mechanical properties of clay through the application of disposable face mask fibers (DFMF). By subjecting the reinforced specimens to a comprehensive series of unconfined strength tests, it was found that adding DFMF to the base soil decreased the maximum dry unit weight (MDUW) and increased the optimum moisture content (OMC). The study examined the effects of DFMF content on the compounds, revealing that a maximum increase of 0.2 in DFMF content improves their unconfined compressive strength (UCS); Therefore, 0.2% mask DFMF content was noticed to be the optimum DFMF content, which constituted maximum strength.