Reusing COVID-19 personal protective equipment wastes for pavement base, subbase, and subgrade applications

Since 2019, the coronavirus disease (COVID-19) pandemic has caused a substantial increase in personal protective equipment waste generation, resulting in significant environmental concerns. In addition, the expansive clay subgrade (ECS) must be stabilized prior to pavement construction because of its unfavorable engineering properties. The use of recycled concrete aggregates (RCA) in pavement bases/subbases offers a sustainable solution to decrease the demand for quarry materials and waste pile-up. However, RCA should be reinforced for base and subbase applications because of its low shear and dynamic properties. This study explores an innovative waste solution by recycling shredded nitrile gloves (SNG) to stabilize clay subgrades and reusing discarded shredded face masks (SFM) to treat RCA for base/subbase applications. A series of experiments including compaction, unconfined compression strength, and repeated-load triaxial tests were conducted. The test results showed that the incorporation of SNG and SFM improved the strength and stiffness of the pavement layers. The addition of 1.5% SNG to ECS resulted in the highest unconfined compressive strength (UCS) value (315.50 kPa) and highest resilient modulus (Mr) (79.98 MPa). Furthermore, introducing 1% SFM into RCA increased the UCS and Mr to peak values of 216 kPa and 314.35 MPa, respectively.