Integrating waste valorization into engineering education: Experiential learning with powdered banana peel as a sustainable cementitious materials

Global cement production contributes about 7 % of CO 2 emissions, underscoring the need for sustainable alternatives. This study investigates the feasibility of using powdered banana peel (PBP), an abundant agricultural waste, as a supplementary cementitious material in mortar. Mortar mixes containing 0 %, 0.2 %, 0.6 %, and 1.25 % PBP by binder weight were tested for flowability, setting time, compressive strength, and microstructure. Incorporating 0.2–0.6 % PBP improved workability, while higher contents reduced flow and delayed setting. The 0.2 % PBP mix achieved the highest 28-day compressive strength of 61.8 MPa, surpassing the control (52.4 MPa), and exhibited a denser microstructure with typical hydration products including calcium silicate hydrate (C–S–H) and portlandite (Ca(OH) 2 ) confirmed by XRD and SEM analyses. These results indicate that low-dosage PBP can serve as a sustainable supplementary cementitious material, reducing cement use without compromising mechanical performance. Moreover, integrating this research into engineering coursework provided experiential learning in waste valorization and sustainability.