Static and dynamic behaviors of granular soil reinforced by disposable face-mask chips

The stock of disposable face masks has climbed steadily due to COVID-19, which results in an urgent worldwide environmental problem. This investigation aims to assess the potential of using waste mask chips (MC) as reinforcement in granular soil. To evaluate the mechanical properties of the mask chips - granular soil mixture (MSM), a series of monotonic and cyclic triaxial tests with different confining pressures and MC contents are conducted. Then, the shear behaviors of MSMs are quantified from both static (strength, stiffness, dilatancy) and dynamic (energy absorption capacity, resilient modulus, deformation) perspectives. Furthermore, based on the static and dynamic indexes, the effects of adding MC into granular soil are comprehensively analyzed. All experimental results indicate that the MSMs exbibit an increase of shear strength and a reduction of shear-induced volumetric dilation, but a decrease in stiffness. The addition of MC also leads to an increase in energy absorption but will not affect the cumulative strain of MSMs. Thus, MC has great potential to be used in the embankment construction of road and railway, backfill or reclamation construction, and so on. This experimental study provides a new perspective and thought on the recycling of waste face masks in civil engineering.