Effect of waste COVID-19 face masks on self-compacting high-strength mortars exposed to elevated temperature

During the pandemic, it becomes customary to wear a disposable surgical (face) mask (SM) to guard against coronavirus illness 19 (COVID-19). However, because existing disposal procedures (i.e., incineration and reclamation) emit hazardous substances, vast generations of contaminated surgical masks pose an environmental risk. Therefore, many studies are currently being carried out worldwide to dispose of SM. The easiest and cheapest of these methods is the disposal of SMs in cement-based composites. This study cut waste SMs to macro size and used them in cement-based composites such as polypropylene fiber. The elevated temperature resistance of cement-based composites decreases as their compressive strength rises. Low-melting materials like polypropylene fiber are utilized to improve the high-temperature resistance of cement-based composites. Therefore, SM with a low melting temperature was used in the design of the mixtures. SM was added to the mix at rates of 0.3, 0.5, 0.8, and 1 by weight of cement. As the SM ratio increased, the workability of the mixtures decreased. Water absorption and apparent porosity increased as SM reduced the workability of composites. The mixes' 28-day compressive strength ranges from 36.6 to 79.4 MPa. It was observed that flexural strength raised in some mixtures when SM was used. In the mixes using 0.5 % SM, about 40 MPa compressive strength was obtained after 800 °C. Additionally, SEM images showed that SM changed into microfibre during mixing. As a result, it has been determined that SM can be used at low rates to increase the elevated temperature resistance of cement-based composites.