Experimental evaluation of magnetite powder and ilmenite powder as novel promising cementitious materials for eco-friendly high-performance mortar

In the quest for sustainable construction solutions, This study investigates the utilization of magnetite powder (MP) and ilmenite powder (IP), sourced from Egyptian black sand, as novel and environmentally sustainable substitutes for cement in high-performance mortar. Seven mortar mixes were developed, integrating MP and IP at substitution rates of 10 %, 20 %, and 30 %, and their physical, mechanical, and microstructural characteristics were meticulously assessed. The pozzolanic activity of MP and IP was confirmed using strength activity index (SAI) and thermogravimetric analysis (TGA), establishing their viability as supplemental cementitious materials (SCMs). The testing results indicated substantial enhancements in mortar performance. A 10 % substitution of cement with IP led to a 20 % enhancement in compressive strength relative to the control mix. Furthermore, MP-enhanced mortar maintained 85 % of its strength after exposure to 600°C, demonstrating exceptional fire resistance. Workability studies indicated that MP and IP enhanced flowability, resulting in flow widths increasing by as much as 15 %. Ultrasonic pulse velocity experiments corroborated improved microstructure density, especially at the 10 % replacement level. Advanced methodologies, including scanning electron microscopy (SEM) and X-ray diffraction (XRD), shown that MP and IP promote the synthesis of calcium silicate hydrate (C-S-H) gels, hence improving durability and diminishing porosity. These findings highlight the viability of MP and IP as sustainable alternatives to cement, providing superior mechanical qualities, fire resistance, and workability, while reducing the environmental footprint of construction materials. This study establishes a foundation for further research on the utilization of these materials in sustainable construction techniques.