Mechanical behavior of sands reinforced with shredded face masks

Abstract

The rapid response to the COVID-19 pandemic has resulted in increased municipal waste in the form of used face masks (FMs), which pose a global threat to the environment. To mitigate this, the study explores the applicability of shredded FMs as alternative reinforcing material in sands. Laboratory-grade Ottawa sand and naturally collected sea sand are adopted as the base sands for testing. The primary physical properties of the base materials and the FMs are first examined, and the soil particles are imaged via scanning electron microscopy. Thirty consolidated undrained (CU) triaxial compression tests were conducted to evaluate the effects of the weight fraction of FM, FM length, and the initial effective mean stress on the undrained shear strength parameters of the sands. The experimental results proved that FM inclusion can lead to a substantial improvement in the undrained shear strength of the sands; however, such improvement was sensitive to the initial effective mean stress, with higher undrained shear strength gains associated with lower initial effective mean stress. For a given FM content, the critical state ratio and angle of friction at the critical state increased with the FM length. Finally, the results revealed that FM-reinforced sands exhibit dilative and strain-hardening behaviors.

Use of polypropylene fibers extracted from recycled surgical face masks in cement mortar

“…Upon adding 1–2 % of shredded face masks (SFMs) to recycled concrete aggregates (RCA) for pavement bases and subbases, the unconfined compressive strength and resilient modulus of the blends of SFM and RCA increased because the FMs served as a reinforcing agent when bonded with RCA [22] . Furthermore, to reduce the amount of surgical mask waste, Ghadr et al [23] described the use of SFMs as a reinforcing material in sand. According to their experimental results, using FMs may significantly increase the undrained shear strength of the sand.…”

Reutilization of solid wastes to improve the hydromechanical and mechanical behaviors of soils — a state-of-the-art review

“…Because the general compositions of PM are sugar, fiber, crude wax, crude protein, SiO 2 , CaO, P 2 O 5 , MgO, and total ash (Table 8 ) [ 86 ], it has the potential for use in soil stabilization. For example, fiber, as a tension-resisting material, could be used to reinforce soil to improve its shear strength, density, and compressibility [ 87 , 88 ]. Notably, if the organic content of PM (fiber) exceeds a certain amount, it may be detrimental to stabilization [ 44 ].…”

“…Energy consumption and carbon production during incineration often exceed the amount stipulated in the carbon neutralization policy agreed upon by many countries. Meanwhile, FMs, which are nonbiodegradable, reportedly take hundreds of years to break down in landfills [ 87 ].…”

“…In general, the main components of the FM are nonwoven fabric, melt-blown nonwoven fabric, and polypropylene composite fiber [ 87 ]. Because of their flexibility, they have the potential to improve soil properties.…”

Experimental Study on the Mechanical Behavior of Sandy Soil Reinforced by Disposable Face Mask Chips under Different Stress Paths

“…The size of the whole mask after unfolding is 175 mm × 95 mm. Considering the relatively large size of the whole mask compared with the sample size, to ensure the mask fiber having a good contact with the soil particles and to maintain an approximate aspect ratio relative to the fully unfolded mask, we cut the masks removing ear bands and nose clips into MCs with a cross-section size of 10 mm × 5 mm as suggested by Ghadr et al [20]. Since disposable medical surgical face masks produced in mainland China are all subject to YY 0469-2011 [21], their specifications and physical properties are similar.…”