Experimental and material characterization of composites, including waste iron and marble powder

Due to its fine particle size, waste marble slurry originating in cutting and processing units mixes into the air after drying, causing environmental and health problems in nearby areas. On the other hand, large amounts of iron particles are generated as metalworking industry waste, affecting the environmental system. In this study, 0%, 10%, and 20% marble powder (instead of cement) and iron particles (instead of fine aggregate) were used in mixtures, and the composites produced were subjected to two different curing periods: 7 and 28 days. The physical, mechanical, microstructural, and thermal properties of the fresh and hardened composites were ascertained via bulk density, consistency, porosity, water absorption, capillary water absorption, strength tests, particle size distribution, X-ray diffraction (XRF), X-ray fluorescence (XRF), scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS), and thermogravimetric analyses (TGA). The results revealed that minimum water absorption (8.5%) and porosity (19.8%) values were achieved in 28-day composites produced with 10% marble-20% iron wastes among all composites. Thus, iron particles substituted for natural aggregates were mainly responsible for the increase in mechanical performance. A maximum flexural strength of 5.9 MPa and a compressive strength of 26.7 MPa were observed in 28-day composites containing 0% marble-20% iron wastes. Furthermore, capillary water absorption tended to decrease with the substitution of 10% marble powder.