Reinventing concrete: Sustainable nano-alumina from metallic waste-cans and nano-ferrite for next-generation green magnetite heavyweight concrete

Abstract

For the first time, sustainable nano-alumina, obtained from metallic waste-cans, is employed in green heavyweight magnetite concrete (GHMC). The GHMC mixes comprised fixed contents of 500, 125, 60, and 27.4 kg/m3 of cement, granulated blast furnace slag (GBFS), silica fume, and superplasticizer (SP), respectively. The benefits of typical magnetite heavyweight concrete was exploited alongside various percentages of research variables in different 11 mixes. The Sand (S) was used as a replacement for fine magnetite (FM) by (25 %, 50 %, 75 %), steel reinforced fiber (SRF) was added by (1 %, 1.5 %). Moreover, the nanoparticles included nano-Alumina (NA) by (2 %, 3 %, 4 %), nano-ferrite powder (NF) by 2 %, and 2 % NA+2 % NF. The effects of sand, SRF, NA, and NF were studied on slump, wet, dry, and oven dry densities, compressive strength (fc) and tensile strengths (ft), water absorption% (Wa%), electrochemical attack with chloride and sulfate, and thermogravimetric analysis (TGA), microstructure (SEM), and gamma-ray attenuation coefficient (LAC-μ, HVL, v) as shown in F ig. 1. The results revealed that adding 25 % sand, 1.5 % SRF, and 2 % NA+2 % NF boosted all of GHMC's tested properties. Although the replacement of 25 % sand slightly reduced the density of GHMC, it improved GHMC's workability, mechanical properties, and durability. Adding 1.5 % SRF resulted in an enhanced density as well as it improved all mechanical properties and durability. The fc, ft, and WA%, were enhanced by 31 %, 70 %, and 38 % at 28 days of age. The mixes incorporating 2%NA were better than those incorporating 2%NF for all testing properties. More improvements were noticed due to adding NA up to 4 %. Moreover, the mix incorporating 2 % NA+2 % NF had the best results compared to other nanoparticles percentages. For example, the dry density, fc and ft, and Wa% were improved up to 3.5 %, 66 %, 216 %, and 68 % at 28 days of age. Furthermore, the residual fc due to the exposure to chloride and sulfate was improved by 87 % and 78 % after 28 days, respectively. The TGA% at 1000 °C improved to 98.73 %, and LAC-μ improved by 83–102.4 %.