Utilization of Non-degradable Bio-medical Waste Ash as a Partial Replacement of Cement

The disposal of non-degradable biomedical waste presents environmental and waste-management challenges, highlighting the need to investigate safe and responsible utilization routes. This study experimentally investigated the use of incinerated biomedical waste ash (BMW) as a partial replacement for ordinary Portland cement in M30-grade concrete. Cement was replaced with BMW at 0%, 5%, 10%, 15%, and 20% by mass. Compressive, splitting tensile, and flexural strengths were evaluated at 7, 14, 28, and 56 days, while ultrasonic pulse velocity (UPV) and rapid chloride ion penetration testing (RCPT) were used to assess selected concrete-quality and durability indicators. Scanning electron microscopy (SEM) was used to examine the microstructure of the 10% BMW mixture. Among the mixtures investigated, CB10 exhibited the highest compressive strength, reaching approximately 50 MPa, UPV of 4325 m/s and an RCPT charge passed of approximately 989 coulombs at 56 days. The SEM image of CB10 shows features interpreted as C–S–H, ettringite, pores, and cracks; however, this image alone does not establish the microstructural mechanism responsible for the superior performance of CB10. Results showed that 10% BMW the ultimate strength and 15% BMW obtained similar to conventional concrete. Graphical abstract