The effects of different-angled placements of waste face masks on the shear strength of granular soils Farklı açılarda yerleştirilen atık maskelerin ayrık daneli zeminlerin kayma mukavemeti üzerindeki etkileri

Following the COVID-19 pandemic, the rapid increase in single-use face mask waste has led to significant environmental concerns. This study investigates the potential reuse of face masks as a reinforcing material in soils through direct shear tests. In addition, the masks placed at specific angles aim to shed light on the influence of different orientations of geosynthetics, which has not been sufficiently addressed in the literature. The outer layer of a three-ply disposable face mask was cut into 60 × 60 mm squares and embedded at the mid-height of the soil specimen with various orientations relative to the horizontal (0°, 5°, 10°, 15°, 20°, and 25°). The tests were conducted on poorly graded sand (SP) specimens prepared at relative densities of 60% and 80%. The findings indicate that both relative density and mask orientation significantly affect the shear strength of the soil. In particular, the inclined placement of the waste mask highlights the role of orientation in mobilizing soil–reinforcement interaction. Overall, waste face masks can be repurposed as sustainable geosynthetic materials for soil improvement. This approach offers an environmentally friendly solution for recycling and reusing the increased volume of waste generated during the pandemic period.